My Ledger Nano S suddenly reseted once. I didn't even try to put my PIN, and it just reseted when I touched the device while plugged in.
That's scary.
It's a well-known bug in 1.5.5 firmware, and Ledger says that this should be fixed in new firmware which is scheduled for Q4 this year. I try to get some info about release date, but only thing I find is few posts on Reddit that Ledger is testing new firmware and that it should be available soon.
I have to admit that even though I have seed backup, I wouldn't want something like this to happen to me. I can only imagine when something like this happens to someone who is not quite aware of how things work.