just chiming in, common to have, and my home controller, shop, and a few customers have all done this. it has never of course read that high, usually 3hrs or so. It does not happen on any reoccurring thing, such as power outages, etc that I can tell. Just get a new plate, or like I usually do, replace the whole thing. the newer ones are a bit nicer anyhow.
all is fair in love and grass!
Man, it smells like sheet, do you smell that!!