Is this new design part of some split personality or something? I've seen a number of pictures like this, but I never saw her in SZS, ZSZS, or GSZS. Perhaps a manga or drama CD event?
It was in both, it was the episode/chapter where everyone was getting over-charged. She turned back after punching a wall(Nozumu), verbally abusing a parental figure(Nozumu), and trolling on an internet forum(also Nozumu). I believe she had no memory of the events.