From r/ublockorigin:

"For uBO users:

A potential fix has been published which may solve the detection issue for many users.

Click here to receive the fix, and then restart your browser.

Users will also receive the fix automatically in a few hours.

It is important that everyone understands that there are many reasons for YouTube adblock detection, and the fix may not be applicable for all cases.

If the fix doesn't resolve the issue for you, then please follow ALL of the instructions in the YouTube Mega Thread, including how to properly report issues.

For uBO Lite (uBOL) users:

A new uBO Lite (uBOL) thread has been created on GitHub for YouTube issues, and this is where all uBOL-related issues with YouTube should be posted.

https://github.com/uBlockOrigin/uAssets/issues/28707

The potential fix for the YT detection issue will be included in the next release of uBOL.

Please note that filters are only updated in uBOL when a new version is released, and users will need to wait until then for the fix. There is no exact date for when that will happen, but it should be relatively soon."

Source: https://old.reddit.com/r/uBlockOrigin/comments/1l47bqa/youtube_detection_ads_or_breakages_including/