When dragging and dropping an image from FF 20/21 into AI CS6, it forces elements on the art board to be displaced.
The image dragged into the app will plop into the middle of the art board, and anything in the file just gets moved.
Where it gets moved to is inconsistent- but it appears to always move on a diagonal.
Probably one of the weirdest things I've ever seen AI do, in 10+ years...