That’s very strange. I would call and ask what’s gone on. Keep an eye on him like you would anyway and take him back in tomorrow. How often did they check his temp? Was the room hot? Did he have layers on? To cause a high reading. What was he meant to be eating? Was it normal food? Had he eaten previous so wasn’t hungry? What did they do to try to engage him? Was he just having a quiet hour? Was he tired? Was others being noisy so wanted abit of distance? How long had they been “tracking” him for? Definitely in need of some answers if it was me.
I would definitely be giving them a call o emailing telling them what happened when he got home and notifying he will be in tomorrow.