I open a video and i see an ad on youtube again, i think ad block is not working properly to block ads from youtube.
That happens very few times. Twice in 365 days lets say. Very rare, but ok.
Can you try clearing data on:
And also clearing all youtube cookies via the
Cookies. then refresh the YT page, and then re-login.
That sometimes happens to me too. it happens twice in a year or its just the ads for the content creators monetisation