Okay, so this is really weird. I'm working on animation and now suddenly in the last few weeks there are black splotches that appear behind several symbols. This started with Flash, but then I updated to Animate to see if that would fix it - it got better with the update but not completely gone. If I select to edit that symbol in Photoshop, the splotches are not there, but they do appear when I run the SWF test preview and in exports.
The size and shape of the splotches is not consistent from frame to frame, and sometimes it doesn't appear at all. See screen caps below of an example of this glitch.
Any idea what causes this or how to get around it?