I have a Samsung with this feature. It rebooted overnight and this morning it was in BFU state with several mail and sms notifications. It was also connected to wifi and the cellular network.
It was true for my Galaxy S22, and is currently true with reboots after update. And yes, early on I had a situation where the phone rebooted overnight and remained stuck on the lock screen while disconnected from networks, until I woke up and noticed. Fortunately I didn't miss anything important, but after that I immediately reviewed all settings and disabled anything that could reboot the device automatically (including updates, which are set for manual installation now).
I have a Samsung with this feature. It rebooted overnight and this morning it was in BFU state with several mail and sms notifications. It was also connected to wifi and the cellular network.