I've gotten the warning, but I just close the window and watch the video. Is that how it's supposed to work? Because, if so, it's only a minor annoyance.
Never got that far for me. Went through Ublock's steps to force update filters and clear cache a couple of times.
Occasionally I won't be able to interact with the UI. No scrolling etc. Since I also run a YouTube enhancer (with it's add block turned off), the video is automatically full screen, 2x speed and auto plays.