I have UBlock installed on Firefox and what is pictured here is what has been happening for every video that I’m clicking on. Panning doesn’t make the video play either. I tried that. It’s not my internet connection since the videos and ads that you can’t even skip and pause when you tab out play just fine on Chrome. In the days before this happened I got several popups from YouTube saying that adblockers aren’t allowed after months of browsing YouTube ad-free without issue
I’ve had this happen when using VPN. I also tried disabling ublock, but I get this behavior for 5-10 seconds before the video loads. I get no such behavior on Chrome.
This is probably another attempt at Google degrading the experience for people not using Chrome.