Pretty sure Pai is bugged, at least when the CPU is controlling her. Just dicking about in Arcade on Rookie to unlock the costumes of characters I don't use, AI-controlled Pai not only busted out a 17-hit juggle (I didn't think it was even possible in DOA for a juggle to sustain long enough to get that many hits, don't know if that is an additional bug/error with her, though even if it's legit she shouldn't be doing that stuff on Rookie!), but twice she warped from knocked down to doing a standing throw. Literally, I knocked her down and a fraction of a second later, before the knockdown animation even finished, she was throwing me. And no, it wasn't a hold or anything. It was her neutral throw and she performed it directly after being knocked down. She also managed to hi counter my hi counter; 'hi counter' flashed up on both sides of the screen at the same time, her mid kick hold animation played but neither of us took any damage.
I've thought her AI seemed even more input-readingly broken than the rest of the game, but the matches I just had confirm it: Pai is straight-up glitched, at least when it's the AI's character.