I've been getting it off and on the last few days, oddly only on one PC still running 10 but everything else with FF/UO is up to date. Nothing on two 11 machines so far, with all signed in on the same google account.
I don't need to, I don't see any popup, I can watch videos on YouTube just fine without changing anything in uBlock Origin's settings or manually updating it.
Do it anyway if you want that to continue. It's generally a good practice anyways since filter updates are pushed regularly with old redundant strings removed and new filters added, for all sites, not just YouTube.