One of mine slid off in what sounds like the same manner.
I used JB Weld on it and didn't touch it for two days. Seems to be fine now (although, admittedly, I AM treating that one a fair bit more gently at the moment). Was going to try some Gorilla Glue (my usual go-to for daily muck-ups), but as the fellas stated I was kinda' iffy about it being around the heat.
Hope it works out for you, OP!