What are you using for an adblocker? I'm using uBlock (I thought it was uBlock Origin but apparently not now that I'm looking), and it also stopped blocking YouTube ads. (When it did block ads I'd have a 15-30 second black screen that I had to wait through.)
ublock origin is what you want to be using. ublock was the original project and the maintainer gave up maintenance to someone else. It didn't work out, so he came back and forked it as ublock origin. If you are having problems with ublock origin, read the troubleshooting section of the docs (or whatever they call it)
