I also have auto update on both firefox and ublock origin (firefox macos) and if I am sleepless and pulling up youtube around 1am-4am youtube seems to push updates around then and I'll see the skip ad button or the yellow ad timer bar with no video or sound. It appears that, as predicted by some in a previous thread about this topic, that there is an arms race between the ublock and youtube devs

the powerful devs at ublock maintain their struggle