I got this today when compiling an FLA into which I’d dropped some new assets. After much head scratching, it turns out that the problem was a movieclip which had a filter applied, wrapped in a Button symbol. I got around this by turning the button into a MovieClip symbol (with _up, _over labels, etc). There are other things that cause this. I narrowed down the problem by pasting the new assets individually, and then guiding the layers of the new symbols out one by one.