diff --git a/src/devices/nm-device.c b/src/devices/nm-device.c
index 46378b63f6..194f634ce6 100644
--- a/src/devices/nm-device.c
+++ b/src/devices/nm-device.c
@@ -3321,16 +3321,8 @@ ip4_config_merge_and_apply (NMDevice *self,
 		goto END_ADD_DEFAULT_ROUTE;
 	}
 
-	connection_has_default_route
-	    = nm_default_route_manager_ip4_connection_has_default_route (nm_default_route_manager_get (),
-	                                                                 connection, &connection_is_never_default);
-
-	if (   !priv->v4_commit_first_time
-	    && !nm_device_uses_assumed_connection (self)
-	    && connection_is_never_default) {
-		/* If the connection is explicitly configured as never-default, we enforce the (absence of the)
-		 * default-route only once. That allows the user to configure a connection as never-default,
-		 * but he can add default routes externally (via a dispatcher script) and NM will not interfere. */
+	if (nm_device_uses_generated_assumed_connection (self)) {
+		/* a generate-assumed-connection always detects the default route from platform */
 		goto END_ADD_DEFAULT_ROUTE;
 	}
 
@@ -3339,6 +3331,18 @@ ip4_config_merge_and_apply (NMDevice *self,
 	 * leases for them, so we must extend/update the default route on commits.
 	 */
 
+	connection_has_default_route
+	    = nm_default_route_manager_ip4_connection_has_default_route (nm_default_route_manager_get (),
+	                                                                 connection, &connection_is_never_default);
+
+	if (   !priv->v4_commit_first_time
+	    && connection_is_never_default) {
+		/* If the connection is explicitly configured as never-default, we enforce the (absence of the)
+		 * default-route only once. That allows the user to configure a connection as never-default,
+		 * but he can add default routes externally (via a dispatcher script) and NM will not interfere. */
+		goto END_ADD_DEFAULT_ROUTE;
+	}
+
 	/* we are about to commit (for a non-assumed connection). Enforce whatever we have
 	 * configured. */
 	priv->default_route.v4_is_assumed = FALSE;
@@ -3942,16 +3946,8 @@ ip6_config_merge_and_apply (NMDevice *self,
 		goto END_ADD_DEFAULT_ROUTE;
 	}
 
-	connection_has_default_route
-	    = nm_default_route_manager_ip6_connection_has_default_route (nm_default_route_manager_get (),
-	                                                                 connection, &connection_is_never_default);
-
-	if (   !priv->v6_commit_first_time
-	    && !nm_device_uses_assumed_connection (self)
-	    && connection_is_never_default) {
-		/* If the connection is explicitly configured as never-default, we enforce the (absence of the)
-		 * default-route only once. That allows the user to configure a connection as never-default,
-		 * but he can add default routes externally (via a dispatcher script) and NM will not interfere. */
+	if (nm_device_uses_generated_assumed_connection (self)) {
+		/* a generate-assumed-connection always detects the default route from platform */
 		goto END_ADD_DEFAULT_ROUTE;
 	}
 
@@ -3960,6 +3956,18 @@ ip6_config_merge_and_apply (NMDevice *self,
 	 * leases for them, so we must extend/update the default route on commits.
 	 */
 
+	connection_has_default_route
+	    = nm_default_route_manager_ip6_connection_has_default_route (nm_default_route_manager_get (),
+	                                                                 connection, &connection_is_never_default);
+
+	if (   !priv->v6_commit_first_time
+	    && connection_is_never_default) {
+		/* If the connection is explicitly configured as never-default, we enforce the (absence of the)
+		 * default-route only once. That allows the user to configure a connection as never-default,
+		 * but he can add default routes externally (via a dispatcher script) and NM will not interfere. */
+		goto END_ADD_DEFAULT_ROUTE;
+	}
+
 	/* we are about to commit (for a non-assumed connection). Enforce whatever we have
 	 * configured. */
 	priv->default_route.v6_is_assumed = FALSE;