Recently it has stopped triggering again though. I have no idea why.
Instead they spread their updates over users 0.1% at a time over an hour or so. That way if youtube stops working for that fraction of users, they can cancel and rollback the update.
Sometimes this means that you might be in that tiny fraction of users who gets a change before the devs who maintain the UBO lists, and sometimes that change is related to ads.
(It's only happened to me twice in the last 2 years)
In this case, you don't need to mess around with other extensions, you just need to wait an hour or so until those devs have seen Google's changes and they can push their own updates to reblock the new ads.
If you want it to go faster, you can go to the github issues pages for the filterlists and they have instructions for how to get uBlock Origin to generate a blob of debug info to post on github to speed up their updates.
Part of me was considering just self-hosting an alternative YT frontend. At this point I'm sorta happy with how YT slowly has decreased its usage in my life
There's plenty of losers out there who can't or won't use ad-blockers that they can make their ad money on; trying to harass the 20% of users who use ad-blockers is just an arms race they can't win.
Interestingly I just tried Chrome (Canary build) with uBO and I'm getting ads... :o