Uhh this is not a normal situation for Chrome / uBlock users. I use Chrome and uBlock as do hundreds of thousands of other people and Youtube videos load just fine.
They mentioned background tabs: I see it in Firefox (with uBlock) when it's a tab I've had sitting in the background for hours. Usually the only fix is to copy the URL and reopen it in a few tab, refreshing doesn't work when it gets into this state.
It feels like a weird combination of caching, some key expiring, and how YouTube doesn't finish loading the video until you view the tab.
