Flash:Flickering Animation, dissapearing animation => corrupted symbol August 6, 2008

This is something I've hit a few times across several projects.  At some unknown event, animated movie clips will start flickering, like if you have a character the head will start to dissapear on or off.  Once one clip is broken, EVERY animation across the Fla will have flickering issues.  Like simple tweens will show the first few frames, cut out completely then show the last.

Not sure how this is caused, guessing it's more frequent if your merging Fla's.   The only solution I've found is going through animation by animation and trying them out in a separate Fla.  Finding the one that flickers, and deleting it and replacing it with a backup will correct...the entire file!