I thought this was consistent, and simply Traya and Sion's "start of turn" order had been flipped. As a fix I had been hitting opposing Traya with my Sion, and using my own Isolate on opposing Sion. However, it seems completely inconsistent. Sometimes Sion taunts when opponent has pain, but sometimes he doesn't. Moreover, I could swear that once or twice he has taunted even though there was no pain at all. This is very broken, and makes Traya mirrors a real mess of a matchup.