Since today, youtube videos will not synchronize with others and the play/pause button is grayed out. This only happens on my account ( I tried a different one). It also does not happen in Incognito mode. I narrowed the problem down to a cookie called __Secure-3PSID. If i delete it it will work for a short while until I play a regular Youtube Video then everything gets broken again (grayed out play button and so on).
I have tried disabling extensions, clearing all browsing data, etc.