If you disabled the list previously, enable it back.
Close all previously opened YT tabs and try in a new one.
Just a reminder: Please always treat disabling lists as a last resort/temporary solution type of thing. Without that list, you won't be receiving important filter updates and will likely encounter ads after a while. So don't keep it disabled forever - verify that it's still necessary (daily?).
From the uBO subreddit: https://old.reddit.com/r/uBlockOrigin/comments/1etvawp/youtube_ads_detection_breakages_2024_08_16_ubo/m31kbkw/
There was just an update to Quick fixes. Please test if it works for you.
Just a reminder: Please always treat disabling lists as a last resort/temporary solution type of thing. Without that list, you won't be receiving important filter updates and will likely encounter ads after a while. So don't keep it disabled forever - verify that it's still necessary (daily?).