YouTube tests server-side ads to make your coveted blocker obsolete
Yahoo
https://www.yahoo.com/tech/youtube-tests-server-side-ads-214747597.html#:~:text=What%20you%20need%20to%20know%201%20A%20discovery,your%20device%20as%20a%20separate%20entity.%20More%20items
YouTube has been spotted testing server-side ads, which could pose a problem to ad blockers.