Lots of issues with movie clips becoming "additive"

Been having a lot of problems with movie clips suddenly appearing as if the "ADD" blending mode is applied. I did notice if I change the default renderer to cache as bitmap from "Original (no change)" that will fix the issue, but only on that particualr frame. It SEEMS to appear for no apparent reason and just started happening recently. Anyone else having these issues, and is there a global setting that might fix it?? It is happening on most files, and I was able to recreate it from a new doc pretty easily. note that NO blending modes are currently selected on any MC in this pic. Also, If I add a bitmap under the "Tree Bitmap" layer, the issue goes away. When I delete the layer, the issue comes back. Losing my mind....been using Flash forever and never seen this

Thanks for any help!

Mike