I've been having the same issue. When I leave the phone on a Qi charger at night, in the morning, I will have the SOS only (about 1 time a week since I update to 16.1 and didnt go away with 16.1.1). Don't know why either. I have to reboot the phone each time.

I looked and I think only one physical sim, but phone says I have access to another sim, that I guess is virtual? Even if that is the answer, e.g. a sim issue, that doesnt really help get to how we can stop this from happening.

edit: I have a 13 Pro Max