D.Va has this weird bug that's hard to replicate that allows her to take ownership of things during her Defense Matrix. I've seen it show D.Va killing people with Concussion Mine and even Hanzo Ult before.
I've never been able to replicate it (or see anyone else do so intentionally) but it's been present in the game and pops up every once in a while.
Typically it's only a User Interface Bug but has no ramifications on the game itself.