Everyone and everything can be hacked, according to Sombra - and apparently, that includes her own highlight intro. The first Sombra hacks her way into the play of the game, but the second Sombra quickly rectifies that issue.
Seeing the two animations stacked up on each other like that is unusual, to say the least - and not just because there were two Sombras in a game for once. The initial highlight intro from green Sombra looks massively weird when it's not interrupting someone else's POTG, but then to see it get interrupted is weirder. A hack within a hack - does this make it hackception?
What makes this worse for the first Sombra is that she probably thought she was getting the play of the game. Her highlight intro pops up, she's all excited, and then suddenly the other Sombra pops in to steal the glory.