The add-on itself is great, but Google seems to have found out how to bypass these ad-blocking tools.
Edit: It's working again, there were some problems even without using adblockers so...
Google actually couldn't really bypass them.

I'm experiencing the same thing. Youtube ads getting around uBlock. I read on the uBlock Reddit page they are working on it. It seems Youtube has found a way to sidestep uBlock. I was getting the message that there was an error on YouTube, but uBlock today said they disabled that feature in order to investigate what Youtube is doing, so you get those ads, but at least you can watch it without disabling uBlock.

uBlock is awesome, Google sucks

its just a beast, internet would be unusable without it.

Adding Adguard filters makes ublock heavier.

God! 唯一真神

Great piece of software that makes using the internet a more efficient and enjoyable experience. Recently though, a new YouTube update seems to have messed with it, YouTube videos won't load at all with the add-on enabled. Hopefully there is a fix for this soon, but even if not, it still works great for many other websites.