Update: This bug seems to have been fixed! At least, I haven't encountered it for a long time.
Just another day with the buggiest software I've ever used. You can see why I don't recommend it.
I call these "green frames." They have missing or incomplete information, and so, they either show up as fully green, or, with frames borrowed from elsewhere... possibly from the frame buffer.
Every time you watch this part, it will look different.
The audio screeching is new in Premiere 2018.
Also, the program permanently freezes almost anytime I click "Save As." That bug is not new.
Also, there are a few hundred other bugs, of varying severity:
https://docs.google.com/spreadsheets/...
Note: The thumbnail image is not a single rendered frame, but a composite of frames from the final bad render.