The Overwatch Uprising update seems to have done a number on the game's reliability. Not only are respawns on capture point maps messing up (assuming you attempt to respawn at the wrong time), but now Symmetra players get a relatively easy-to-execute exploit likely to infuriate the enemy team.
As captured by Xbox console player ShadowTroopR5, it's possible to make her Teleporter invincible -- the translucent portal won't appear, and the can't be interacted with, though enemy players will deploy as normal.
Granted, when it drops you one at a time into a room with a rampaging Reinhardt, that's usually just a lot of kills onto the enemy team.
The trick to it seems easy enough to pull off: you deploy just as you switch over to the shield generator ult. As demonstrated by YouTuber VaugnJogVlog:
He, too, is doing it on the Xbox, though it seems to apply to PC players too.
Note, of course, that this counts as a rather explicit exploit, and is hard to pull off accidentally. Which means that Symmetra players currently abusing it for an edge in competitive play are probably being tagged for a ban wave. But if you find yourself facing a rapidly spawning wave of enemy players coming out of who knows where, you now know not to waste your ult on their Teleporter.
As always, we does not condone the use of exploits. Overwatch devs have not yet made a statement about this bug.