Found similar bugs reported in the community and some workarounds but nothing that exactly matches the problem I'm experiencing.
While playing the timeline or scrubbing... one video track will randomly turn black for a few frames then come back. it happens randomly throughout the entire timeline. if I scrub back over those frames a few times it will show them and I can even start playback again and see those frames. but then just blank out somewhere else. It only does it on one video track. if I have more than one with a mask, the track with the mask will turn black except for the mask which still shows the bottom track as it should..with no black. But if I only have one video track then the video just blanks out for a few frames on that track. Doesn't seems to matter what track... it's very random. tested on multiple projects and new projects with different footage sources and formats. seems to make no difference. Attached is track matte and ultra key on the upper video track. but this happens on project on a single track with no effects also.
The Exported video does not have any black frames thankfully. it just doing it while editing which makes it hard difficult to make sure cuts and transitions are happening where I want them. slows down the process significantly but not the end of the world.
Things I have already tried Changing the render from mercury playback engine to software only.
Clearing Media Cache
Resetting all preferences to default.
Been using Adobe CC an entire year with no issue until it updated to version 23 and that's when this problem seemed to start. The only solution so far was to downgrade back to the previous version 22.6.2. .no more blanking out