So I wasn’t too bothered about this when I first watched the video, but I’ve had one or two games where I can actively see the other player exploiting this issue and it’s driving me insane. The general idea of this is to simply tab out and back into your game midway through a match, this for some reason causes mass desync for the player who DIDN’T tab out of their game although it is reversible if they do the same thing back. It’s pretty easy to tell when people are exploiting this, I had a match where a Bison back-dashed fullscreen and stood still for 5 seconds before the desync started to come out of nowhere. This IMO is something that ruins the online experience, having exploits like this only serves to make the online scene more of a joke.
There’s a video that demonstrates what I mean below, a reminder that the player tabbing in will not have any desync issues and only the player who hasn’t tabbed out receives them.
I can vouch for this and say it’s definitely something legitimate, I’d tested it in Battle Lounges with friends also.