diff --git a/src/mm-iface-modem-3gpp.c b/src/mm-iface-modem-3gpp.c
index b72ae0e4..9273f83f 100644
--- a/src/mm-iface-modem-3gpp.c
+++ b/src/mm-iface-modem-3gpp.c
@@ -3713,10 +3713,11 @@ load_enabled_facility_locks_ready (MMIfaceModem3gpp *self,
         g_object_get (self, MM_IFACE_MODEM_SIM, &sim, NULL);
 
         if (sim)
-            g_signal_connect (sim,
-                              MM_BASE_SIM_PIN_LOCK_ENABLED,
-                              G_CALLBACK (sim_pin_lock_enabled_cb),
-                              ctx->skeleton);
+            g_signal_connect_object (sim,
+                                     MM_BASE_SIM_PIN_LOCK_ENABLED,
+                                     G_CALLBACK (sim_pin_lock_enabled_cb),
+                                     ctx->skeleton,
+                                     0);
     }
 
     /* Go on to next step */
diff --git a/src/mm-iface-modem-cell-broadcast.c b/src/mm-iface-modem-cell-broadcast.c
index 32a77535..0776c1c4 100644
--- a/src/mm-iface-modem-cell-broadcast.c
+++ b/src/mm-iface-modem-cell-broadcast.c
@@ -636,14 +636,16 @@ interface_enabling_step (GTask *task)
                       NULL);
 
         /* Connect to list's signals */
-        g_signal_connect (list,
-                          MM_CBM_ADDED,
-                          G_CALLBACK (cbm_added),
-                          ctx->skeleton);
-        g_signal_connect (list,
-                          MM_CBM_DELETED,
-                          G_CALLBACK (cbm_deleted),
-                          ctx->skeleton);
+        g_signal_connect_object (list,
+                                 MM_CBM_ADDED,
+                                 G_CALLBACK (cbm_added),
+                                 ctx->skeleton,
+                                 0);
+        g_signal_connect_object (list,
+                                 MM_CBM_DELETED,
+                                 G_CALLBACK (cbm_deleted),
+                                 ctx->skeleton,
+                                 0);
         ctx->step++;
     } /* fall through */
 
diff --git a/src/mm-iface-modem-messaging.c b/src/mm-iface-modem-messaging.c
index 93cd0ae1..be085bfc 100644
--- a/src/mm-iface-modem-messaging.c
+++ b/src/mm-iface-modem-messaging.c
@@ -1026,14 +1026,16 @@ interface_enabling_step (GTask *task)
                       NULL);
 
         /* Connect to list's signals */
-        g_signal_connect (list,
-                          MM_SMS_ADDED,
-                          G_CALLBACK (sms_added),
-                          ctx->skeleton);
-        g_signal_connect (list,
-                          MM_SMS_DELETED,
-                          G_CALLBACK (sms_deleted),
-                          ctx->skeleton);
+        g_signal_connect_object (list,
+                                 MM_SMS_ADDED,
+                                 G_CALLBACK (sms_added),
+                                 ctx->skeleton,
+                                 0);
+        g_signal_connect_object (list,
+                                 MM_SMS_DELETED,
+                                 G_CALLBACK (sms_deleted),
+                                 ctx->skeleton,
+                                 0);
 
         g_object_unref (list);
 
diff --git a/src/mm-iface-modem-time.c b/src/mm-iface-modem-time.c
index 4f9e7f3f..52ca139a 100644
--- a/src/mm-iface-modem-time.c
+++ b/src/mm-iface-modem-time.c
@@ -153,6 +153,7 @@ typedef struct {
     MMModemState state;
     guint network_timezone_poll_id;
     guint network_timezone_poll_retries;
+    guint session_id;
 } NetworkTimezoneContext;
 
 static void
@@ -191,23 +192,34 @@ update_network_timezone_dictionary (MMIfaceModemTime *self,
 
 static void
 load_network_timezone_ready (MMIfaceModemTime *self,
-                             GAsyncResult *res)
+                             GAsyncResult     *res,
+                             gpointer          user_data)
 {
-    g_autoptr(GError)  error = NULL;
-    MMNetworkTimezone *tz;
+    g_autoptr(GError)            error = NULL;
+    g_autoptr(MMNetworkTimezone) tz = NULL;
+    NetworkTimezoneContext      *ctx;
+    guint                        session_id;
 
-    /* Finish the async operation */
+    session_id = GPOINTER_TO_UINT (user_data);
+
+    /* Finish the async operation first to avoid resource leaks */
     tz = MM_IFACE_MODEM_TIME_GET_IFACE (self)->load_network_timezone_finish (self, res, &error);
+
+    /* Note: may be NULL if the polling has been removed while processing the async operation */
+    ctx = (NetworkTimezoneContext *) g_object_get_qdata (G_OBJECT (self), network_timezone_context_quark);
+    if (!ctx)
+        return;
+
+    /* Check if this is the result of the current poll session */
+    if (ctx->session_id != session_id) {
+        mm_obj_dbg (self, "discarding network timezone load result from old session (session ID %u, current %u)",
+                    session_id, ctx->session_id);
+        return;
+    }
+
     if (!tz) {
-        NetworkTimezoneContext *ctx;
-
         mm_obj_dbg (self, "couldn't load network timezone: %s", error->message);
 
-        /* Note: may be NULL if the polling has been removed while processing the async operation */
-        ctx = (NetworkTimezoneContext *) g_object_get_qdata (G_OBJECT (self), network_timezone_context_quark);
-        if (!ctx)
-            return;
-
         /* Retry? */
         ctx->network_timezone_poll_retries--;
 
@@ -227,7 +239,6 @@ load_network_timezone_ready (MMIfaceModemTime *self,
 
     /* Got final result properly, update the property in the skeleton */
     update_network_timezone_dictionary (self, tz);
-    g_object_unref (tz);
 }
 
 static gboolean
@@ -241,7 +252,7 @@ network_timezone_poll_cb (MMIfaceModemTime *self)
     MM_IFACE_MODEM_TIME_GET_IFACE (self)->load_network_timezone (
         self,
         (GAsyncReadyCallback)load_network_timezone_ready,
-        NULL);
+        GUINT_TO_POINTER (ctx->session_id));
 
     return G_SOURCE_REMOVE;
 }
@@ -253,7 +264,13 @@ start_network_timezone_poll (MMIfaceModemTime *self)
 
     ctx = (NetworkTimezoneContext *) g_object_get_qdata (G_OBJECT (self), network_timezone_context_quark);
 
-    mm_obj_dbg (self, "network timezone polling started");
+    if (ctx->network_timezone_poll_id) {
+        g_source_remove (ctx->network_timezone_poll_id);
+        ctx->network_timezone_poll_id = 0;
+    }
+    ctx->session_id++;
+
+    mm_obj_dbg (self, "network timezone polling started (session ID %u)", ctx->session_id);
     ctx->network_timezone_poll_retries = NETWORK_TIMEZONE_POLL_RETRIES;
     ctx->network_timezone_poll_id = g_timeout_add_seconds (NETWORK_TIMEZONE_POLL_INTERVAL_SEC, (GSourceFunc)network_timezone_poll_cb, self);
 }
@@ -270,6 +287,7 @@ stop_network_timezone_poll (MMIfaceModemTime *self)
         g_source_remove (ctx->network_timezone_poll_id);
         ctx->network_timezone_poll_id = 0;
     }
+    ctx->session_id++;
 }
 
 static void
diff --git a/src/mm-iface-modem-voice.c b/src/mm-iface-modem-voice.c
index b3907e53..d6ea4aae 100644
--- a/src/mm-iface-modem-voice.c
+++ b/src/mm-iface-modem-voice.c
@@ -3019,14 +3019,16 @@ interface_initialization_step (GTask *task)
                           NULL);
 
             /* Connect to list's signals */
-            g_signal_connect (list,
-                              MM_CALL_ADDED,
-                              G_CALLBACK (call_added),
-                              ctx->skeleton);
-            g_signal_connect (list,
-                              MM_CALL_DELETED,
-                              G_CALLBACK (call_deleted),
-                              ctx->skeleton);
+            g_signal_connect_object (list,
+                                     MM_CALL_ADDED,
+                                     G_CALLBACK (call_added),
+                                     ctx->skeleton,
+                                     0);
+            g_signal_connect_object (list,
+                                     MM_CALL_DELETED,
+                                     G_CALLBACK (call_deleted),
+                                     ctx->skeleton,
+                                     0);
 
             /* Setup monitoring for in-call event handling */
             g_signal_connect (list,
diff --git a/src/mm-port-serial-at.c b/src/mm-port-serial-at.c
index ca2cc540..267ebdd5 100644
--- a/src/mm-port-serial-at.c
+++ b/src/mm-port-serial-at.c
@@ -241,7 +241,7 @@ parse_unsolicited (MMPortSerial *port, GByteArray *response)
                                       response->len,
                                       0, 0, &match_info, NULL);
         if (handler->callback) {
-            while (g_match_info_matches (match_info)) {
+            while (g_match_info_matches (match_info) && handler->callback) {
                 handler->callback (self, match_info, handler->user_data);
                 g_match_info_next (match_info, NULL);
             }
diff --git a/src/mm-shared-qmi.c b/src/mm-shared-qmi.c
index d93698a6..f4193b60 100644
--- a/src/mm-shared-qmi.c
+++ b/src/mm-shared-qmi.c
@@ -3111,6 +3111,12 @@ list_configs_indication (QmiClientPdc                      *client,
     self = g_task_get_source_object (task);
     ctx  = g_task_get_task_data (task);
 
+    /* Disconnect list-configs indication right away to avoid re-entry */
+    if (ctx->list_configs_indication_id) {
+        g_signal_handler_disconnect (ctx->client, ctx->list_configs_indication_id);
+        ctx->list_configs_indication_id = 0;
+    }
+
     if (!qmi_indication_pdc_list_configs_output_get_indication_result (output, &error_code, &error)) {
         load_carrier_config_abort (task, error);
         return;
diff --git a/src/plugins/cinterion/mm-broadband-modem-cinterion.c b/src/plugins/cinterion/mm-broadband-modem-cinterion.c
index 3d70cf50..e0cd82d4 100644
--- a/src/plugins/cinterion/mm-broadband-modem-cinterion.c
+++ b/src/plugins/cinterion/mm-broadband-modem-cinterion.c
@@ -1177,7 +1177,7 @@ modem_3gpp_register_in_network (MMIfaceModem3gpp    *_self,
                                               operator_code,
                                               &command,
                                               &error)) {
-        g_task_return_error (task, error);
+        g_task_return_error (task, g_steal_pointer (&error));
         g_object_unref (task);
         return;
     }
@@ -1723,14 +1723,14 @@ ws46_query_ready (MMBaseModem  *self,
 
     response = mm_base_modem_at_command_finish (self, res, &error);
     if (!response) {
-        g_task_return_error (task, error);
+        g_task_return_error (task, g_steal_pointer (&error));
         g_object_unref (task);
         return;
     }
     if (!mm_cinterion_parse_ws46_response (response,
                                            &(result->allowed),
                                            &error)) {
-        g_task_return_error (task, error);
+        g_task_return_error (task, g_steal_pointer (&error));
         g_object_unref (task);
         return;
     }
@@ -1882,7 +1882,7 @@ cops_set_current_modes (MMBroadbandModemCinterion *self,
                                               operator_id,
                                               &command,
                                               &error)) {
-        g_task_return_error (task, error);
+        g_task_return_error (task, g_steal_pointer (&error));
         g_object_unref (task);
         return;
     }
diff --git a/src/plugins/cinterion/mm-shared-cinterion.c b/src/plugins/cinterion/mm-shared-cinterion.c
index aa9b6208..3a703a22 100644
--- a/src/plugins/cinterion/mm-shared-cinterion.c
+++ b/src/plugins/cinterion/mm-shared-cinterion.c
@@ -266,7 +266,7 @@ parent_load_update_settings_ready (MMIfaceModemFirmware *self,
     priv = get_private (MM_SHARED_CINTERION (self));
     update_settings = priv->iface_modem_firmware_parent->load_update_settings_finish (self, res, &error);
     if (error) {
-        g_task_return_error (task, error);
+        g_task_return_error (task, g_steal_pointer (&error));
         g_object_unref (task);
         return;
     }
@@ -276,7 +276,7 @@ parent_load_update_settings_ready (MMIfaceModemFirmware *self,
     ids = mm_iface_firmware_build_generic_device_ids (MM_IFACE_MODEM_FIRMWARE (self), &error);
     if (error) {
         mm_obj_warn (self, "failed to build generic device ids: %s", error->message);
-        g_task_return_error (task, error);
+        g_task_return_error (task, g_steal_pointer (&error));
         g_object_unref (task);
         return;
     }
diff --git a/src/plugins/fibocom/mm-shared-fibocom.c b/src/plugins/fibocom/mm-shared-fibocom.c
index 1f9559c4..9259d080 100644
--- a/src/plugins/fibocom/mm-shared-fibocom.c
+++ b/src/plugins/fibocom/mm-shared-fibocom.c
@@ -343,7 +343,7 @@ parent_load_update_settings_ready (MMIfaceModemFirmware *self,
     priv = get_private (MM_SHARED_FIBOCOM (self));
     update_settings = priv->iface_modem_firmware_parent->load_update_settings_finish (self, res, &error);
     if (error) {
-        g_task_return_error (task, error);
+        g_task_return_error (task, g_steal_pointer (&error));
         g_object_unref (task);
         return;
     }
diff --git a/src/plugins/foxconn/mm-broadband-modem-mbim-foxconn.c b/src/plugins/foxconn/mm-broadband-modem-mbim-foxconn.c
index 9e32df3b..21138c6a 100644
--- a/src/plugins/foxconn/mm-broadband-modem-mbim-foxconn.c
+++ b/src/plugins/foxconn/mm-broadband-modem-mbim-foxconn.c
@@ -276,7 +276,7 @@ parent_load_update_settings_ready (MMIfaceModemFirmware *self,
 
     update_settings = iface_modem_firmware_parent->load_update_settings_finish (self, res, &error);
     if (error) {
-        g_task_return_error (task, error);
+        g_task_return_error (task, g_steal_pointer (&error));
         g_object_unref (task);
         return;
     }
diff --git a/src/plugins/quectel/mm-broadband-modem-quectel.c b/src/plugins/quectel/mm-broadband-modem-quectel.c
index 072e291b..dbf8c427 100644
--- a/src/plugins/quectel/mm-broadband-modem-quectel.c
+++ b/src/plugins/quectel/mm-broadband-modem-quectel.c
@@ -212,7 +212,7 @@ power_off_ready (MMBroadbandModemQuectel *self,
      */
 
     if (!mm_base_modem_at_command_finish (MM_BASE_MODEM (self), res, &error)) {
-        g_task_return_error (task, error);
+        g_task_return_error (task, g_steal_pointer (&error));
         g_object_unref (task);
         return;
     }
diff --git a/src/plugins/quectel/mm-shared-quectel.c b/src/plugins/quectel/mm-shared-quectel.c
index 1bae73e4..9d36583f 100644
--- a/src/plugins/quectel/mm-shared-quectel.c
+++ b/src/plugins/quectel/mm-shared-quectel.c
@@ -152,6 +152,14 @@ mm_shared_quectel_create_wwan_port (MMBaseModem *self,
 /*****************************************************************************/
 /* RDY unsolicited event handler */
 
+static gboolean
+rdy_handler_idle (MMBroadbandModem *self)
+{
+    mm_base_modem_set_reprobe (MM_BASE_MODEM (self), TRUE);
+    mm_base_modem_set_valid (MM_BASE_MODEM (self), FALSE);
+    return G_SOURCE_REMOVE;
+}
+
 static void
 rdy_handler (MMPortSerialAt *port,
              GMatchInfo *match_info,
@@ -162,8 +170,10 @@ rdy_handler (MMPortSerialAt *port,
      * re-synchronize modem and ModemManager states by re-probing.
      */
     mm_obj_warn (self, "modem reset detected, triggering reprobe");
-    mm_base_modem_set_reprobe (MM_BASE_MODEM (self), TRUE);
-    mm_base_modem_set_valid (MM_BASE_MODEM (self), FALSE);
+    g_idle_add_full (G_PRIORITY_DEFAULT_IDLE,
+                     (GSourceFunc) rdy_handler_idle,
+                     g_object_ref (self),
+                     g_object_unref);
 }
 
 /*****************************************************************************/
@@ -475,7 +485,7 @@ parent_load_update_settings_ready (MMIfaceModemFirmware *self,
     priv = get_private (MM_SHARED_QUECTEL (self));
     update_settings = priv->iface_modem_firmware_parent->load_update_settings_finish (self, res, &error);
     if (error) {
-        g_task_return_error (task, error);
+        g_task_return_error (task, g_steal_pointer (&error));
         g_object_unref (task);
         return;
     }
diff --git a/src/plugins/ublox/mm-plugin-ublox.c b/src/plugins/ublox/mm-plugin-ublox.c
index 7921b02f..66eda597 100644
--- a/src/plugins/ublox/mm-plugin-ublox.c
+++ b/src/plugins/ublox/mm-plugin-ublox.c
@@ -113,6 +113,9 @@ ready_received (MMPortSerialAt   *port,
     g_source_remove (ctx->timeout_id);
     ctx->timeout_id = 0;
 
+    mm_port_serial_at_add_unsolicited_msg_handler (port, ctx->ready_regex,
+                                                   NULL, NULL, NULL);
+
     mm_obj_dbg (probe, "received READY: port is AT");
 
     /* Flag as an AT port right away */