That isn't a solution to it. Mine is the same, and I have practically deleted all my apps and wiped my cache. I discovered it mostly happens when I change my fonts or system settings like motion smoothness, and the list is endless. It is a bug in the last update, and I hope the June update will address it.
I imstalled the update 2 days ago and it has restarted every night since. I started the Members app to see who else is affected and it greeted me with the same message.
Has anyone noticed whether the phone's alarms still sound while it's waiting for its first login after an update? Since it waits to apply UI settings, I have a nasty feeling it'll leave me hanging one of these mornings.