There appears to be graphical bug since ver 3.68 where an exhausted ally is not shown as exhausted in game (ie not shaded). This graphical bug occurs on some allies when they are summoned or after they have executed their actions for the turn. It gives the impression that these allies can perform an action even though they are exhausted. I mostly notice this bug when I am using Zhanna on some 5cc+ allies. Others have noticed that it occurs on Priest allies.