Home Assistant 118.3 (venv installation) history not updating

I have had this occurrence twice in the last 2 or 3 weeks, latest 30 minutes ago.

I have some temperature/humidity (rfxtrx) and air pressure (pywws) sensors. This morning I noticed that although the sensors showed current values the history graph for all sensors was flat from just after 04:00 this morning. I restarted HASS and all history grpahs showed a jump to the current values. I only have these sensors plus a couple of WiFi swicthes (D-Link MyStrom).
I couldn’t see anything in the logs although I restarted HASS before checking (sorry). I just updated to 118.5

What could I check? I have influxdb installed and a couple of Grafana grapshs - they seem to show correct values during the same period. I am using mysql (mariadb).

After some searching and checking journalctl & syslog I think I traced the problem and it’s probably this MariaDB purge