Its possible videos were queued in the app but it took at least a minute for the block to land, possibly 2

I think there was an initial block noti and then i was able to watch maybe 5-7 more videos and then another block notification came and that seemed to be when no more could load

Being able to recreate it like that also strongly implies its videos being pre-cached

I went back into the app (so at that point it was definitely the case that the videos were pre-queued) to try and “recreate” my exact experience and i do actually think this was exactly it: