I just experienced this fault. It started yesterday as we where going to bed, had done nothing to my system at that time so completely out of the blue.
This morning I started to search around for a fix.
HA 107.7 (had not updated at that time)
Since I couldn’t get in to the supervisor I was unable to reboot the system. I have SSH add-on (Terminal & SSH) installed, but the somehow the configuration of the port was set to “null”. So I could not get into the system to reboot. The only thing left was to pull the plug
I was lucky and the system booted up fine.
As soon as the system was up I made a new full snapshot.
Then I looked into the ssh problem and found the issue with the port, I changed that to 22 and made sure ssh worked by using the terminal.
Then I updated the system completely to the latest HA and operating system.
So far the system is working fine, I only had one invalid config. That was an add-on from the HACS, spotcast. This add-on had recently stopped working because of Spotify changing some things. I don’t think that caused this fault on my system.
If my SSH would have been working I would have tried this before doing a hard reboot.
This really made me question having my system on an SD card for sure, I have had this install since late last year with no issues and a great setup I rely on. If I have the same fault again I will report back.