Bumping this as once again it has happened, this time in Copperbell mine where the puglist in the party vanished after I suffered a moment of extreme lag and though her hp and actions were registering I could not select her or interact with her at all. Thus I was forced to use Medica whenever I saw she was losing hp as my only means to heal her. As for some reason my party buffs and heals still reacted as if she was there but my single target spells would not.