Reddit user u/McMagicMarv discovered what is assumed to be quite a massive bug in Overwatch involving Symmetra's teleporter. The bug allows two select heroes to do significant damage from seemingly nowhere, blindsiding and confounding their opposition.
Normally, heroes are unable to use any abilities while simultaneously traveling through the teleporter, but it seems that a couple exceptions have emerged. Winston and Wrecking Ball are able to use their leap and piledrive abilities respectively while going through Symmetra's teleporter. This is quite a game-changing bug that can easily get teams sneaky kills or, at the minimum, sneaky damage off when their opponents are least expecting it.
This is crucial, Wrecking Ball players must begin holding down whatever button or key they use to interact with Symmetra's teleporter BEFORE they begin the piledrive action. Once that key is being held, Wrecking Ball players can then gather momentum and height and piledrive down onto Symmetra's teleporter. If done correctly, Wrecking Ball will teleport just before landing on the ground, meaning the piledriver action will still be in effect and the hero will hit the ground on the other side of the teleporter, thus doing damage there instead of where they initiated the animation.
The mechanic works similarly for Winston and his leap ability. Winston players must begin holding down their teleport key or button before using their leap ability. As they leap, while continuing to hold down the teleporter button, they must direct themselves to land on the teleporter. If players have done this then, like Wrecking Ball, Winston should appear on other side of the teleporter while still in the leap animation thus doing damage in a different spot from where the player first used the ability.
It is likely that, once on their radar, Blizzard will move swiftly to address this presumably unintentional mechanic. For now, though, players should keep their eye on any Symmetra teleporter as a leaping Winston or piledriving Wrecking Ball could appear out of thin air and wreak havoc.