Edit: I opened another tab in a separate Firefox container and didn't get the pop-up. I believe I read this shit being account-based when the first reports of Youtube's anti-adblock measures started making the rounds and it seems to be the case still
I've gotten this popup, I just hit the x to close it and then my adblocker/sponsor block works as normal
You'll eventually get a three strikes popup or it'll block you from playing video. Then you have to update uBlock regularly :(
yeah it started making me wait like 10 seconds to close the popup, I grabbed a firefox addon that redirects youtube links to invidious