I get exactly the same thing every night - 12:07 most common - but always between midnight and about 12:33. Has been happening for months. Fine all the rest of the time. I think Virgin Media are manually resetting all the connections at specific times to help their overall broadband due to increased traffic due to covid, but stupidly have not communicated this with their customers.
If any of the secret virgin reboot team happen to read the forums - I don't mind that this happens but 1. communicate it. 2. Please change mine to about 4am as I'm often in the middle of working at midnight and it resets my ssh sessions.