Something similar happened to me in league play one time. I played a grey nymph, used the ability on itself next turn, and then it got reverse timed. When I played it again, after the attack it turned into a cell. My opponent, on the other hand, reported that it looked just like I'd played a cell from hand. We didn't have any screenshots as it was too fast, but I think I did post about it somewhere in the bug forum. (at work atm so can't be bothered to look :p)