[Gameplay][PBE] Rek'sai attack speed?

I was testing Rek'sai on the PBE a minute ago, and near the end of the game my attack speed just suddenly plummeted. I'm not sure what caused it, but I'd just hit level 18, and also just died with a Guardian Angel? But I went from a decent 1.31-ish attack speed, to a 0.91, and it never went back up.