diff -rupN weston-12.0.3.orig/libweston/compositor.c weston-12.0.3/libweston/compositor.c
--- weston-12.0.3.orig/libweston/compositor.c	2024-01-15 15:42:23.723505677 +0000
+++ weston-12.0.3/libweston/compositor.c	2024-01-20 13:27:54.816568920 +0000
@@ -3349,10 +3349,13 @@ weston_output_finish_frame(struct weston
 	 * If timestamp of latest vblank is given, it must always go forwards.
 	 * If not given, INVALID flag must be set.
 	 */
-	if (stamp)
+	/* if (stamp)
 		assert(timespec_sub_to_nsec(stamp, &output->frame_time) >= 0);
 	else
-		assert(presented_flags & WP_PRESENTATION_FEEDBACK_INVALID);
+		assert(presented_flags & WP_PRESENTATION_FEEDBACK_INVALID); */
+
+	assert(output->repaint_status == REPAINT_AWAITING_COMPLETION);
+	assert(stamp || (presented_flags & WP_PRESENTATION_FEEDBACK_INVALID));
 
 	weston_compositor_read_presentation_clock(compositor, &now);