Dashboard configuration gone - howto restore

Hi there,
after updating my HA VM to 202.8.1 yesterday (Supervisor 2024.08.0, OS 12.4, Frontend 20240809.0) I had no issues (some sensor tempalte config stuff that only popped up after restart, but not related)

I went to bed and this morning I checked my energy price on the dashboard (trying to figure out why my boiler started in the middle of the night) and everything was fine. A few hours later I noticed my dashboards were gone.
I can’t recall having done anything in between.

I found a backup from before I got up today, and in there /homeassistant/.storage/lovelace I found my old dashboards.

I used the official smb addon to easily copy over the files (all lovelace*) into the active system (share folder) and then the terminal (addon) to copy them into the system folder (cp /share/lovelace* /homeassistant/.storage/, don’t forget to create a backup always!).
Then it needed a full start (not just reload YAML config) to bring my dashboards back.

This is meant
a) as a quick guide for others
b) question as to why/what happened here?