diff --git a/clutter/clutter/clutter-actor-meta.c b/clutter/clutter/clutter-actor-meta.c
index eba098584a0b724620fe1c9e2d490b65705cb4b2..f90c44e9d94a4d6e4f4f64d86755c91a6880c13d 100644
--- a/clutter/clutter/clutter-actor-meta.c
+++ b/clutter/clutter/clutter-actor-meta.c
@@ -88,6 +88,10 @@ static void
 clutter_actor_meta_real_set_actor (ClutterActorMeta *meta,
                                    ClutterActor     *actor)
 {
+  g_warn_if_fail (!meta->priv->actor ||
+                  !CLUTTER_ACTOR_IN_PAINT (meta->priv->actor));
+  g_warn_if_fail (!actor || !CLUTTER_ACTOR_IN_PAINT (actor));
+
   if (meta->priv->actor == actor)
     return;
 
@@ -293,6 +297,9 @@ clutter_actor_meta_set_enabled (ClutterActorMeta *meta,
 {
   g_return_if_fail (CLUTTER_IS_ACTOR_META (meta));
 
+  g_warn_if_fail (!meta->priv->actor ||
+                  !CLUTTER_ACTOR_IN_PAINT (meta->priv->actor));
+
   is_enabled = !!is_enabled;
 
   if (meta->priv->is_enabled == is_enabled)
diff --git a/clutter/clutter/clutter-offscreen-effect.c b/clutter/clutter/clutter-offscreen-effect.c
index ac4ea98e259deab3411b058bb918d8868d47a64a..0b81c67a8128aa54ba7c6f1415467dfc2b3ca67b 100644
--- a/clutter/clutter/clutter-offscreen-effect.c
+++ b/clutter/clutter/clutter-offscreen-effect.c
@@ -446,13 +446,16 @@ clutter_offscreen_effect_post_paint (ClutterEffect       *effect,
   ClutterOffscreenEffectPrivate *priv = self->priv;
   CoglFramebuffer *framebuffer;
 
-  if (priv->offscreen == NULL ||
-      priv->target == NULL ||
-      priv->actor == NULL)
-    return;
+  g_warn_if_fail (priv->offscreen);
+  g_warn_if_fail (priv->target);
+  g_warn_if_fail (priv->actor);
 
   /* Restore the previous opacity override */
-  clutter_actor_set_opacity_override (priv->actor, priv->old_opacity_override);
+  if (priv->actor)
+    {
+      clutter_actor_set_opacity_override (priv->actor,
+                                          priv->old_opacity_override);
+    }
 
   framebuffer = clutter_paint_context_get_framebuffer (paint_context);
   cogl_framebuffer_pop_matrix (framebuffer);