diff --git a/src/core/execute.c b/src/core/execute.c
index d5a464d6f6..ac19fc0a68 100644
--- a/src/core/execute.c
+++ b/src/core/execute.c
@@ -1927,7 +1927,7 @@ static int build_environment(
                 if (!pre)
                         return -ENOMEM;
 
-                joined = strv_join_full(c->directories[t].paths, ":", pre, false);
+                joined = strv_join_full(c->directories[t].paths, ":", pre, true);
                 if (!joined)
                         return -ENOMEM;