On Chrome browsers (Android, desktop), if you click on the video player to make it full screen, the full screen players closes after a second and the user is bounced to a different location in the topic. This is very similar what was seen with YouTube earlier, but YouTube still works.
This is not-repro on desktop Firefox, so could be Chrome specific.
I am facing the same issue today in Windows desktop Chrome for imgur video onebox
Yes, it looks better here. I think the issue is happening when the topic have more than 20 posts. In that case it is automatically navigating to 20 posts before.
There’s a very long standing bug here with going fullscreen on YouTube videos as well, that was basically impossible to fix due to browser quirks. A meta search should pick it up.