How does this happen: Weird Glitch with REY

So last night during arena I watched my REY do her best impression of Talia:

Rey moves in for her triple hit.....then she retreats to the middle of the table....stands there with a mean ass look on her face there is a 2 second pause then she moonwalks back to her position. The game didn't glitch from what I could tell It was a perfectly executed talia animation

NOW as someone who uses Talia a lot and loves that animation My question is: How does a glitch like this actually happen where a character can suddenly have the animation of another?

Has anyone else seen this before?