Tasmota devices became unavailable few times a day - but HA still receives mqtt updated

This starts to drive me crazy. I have one Tasmota (12.4.0) device that few times a day became permanently unavailable in HA. But even after HA marks it as unavailable it still received mqtt topics with update for this device, it even updates the time since last sensor update but it still stays unavailable:
obraz
On the screen you can see it’s updated “Now” - but it’s also marked as unavailable for last 20 minutes.

The device restart fixed issue for a while. I’ve already did factory reset and Tasmota downgrade, removed and re-added it to HA, switched to static IP from DHCP, removed UniFi integration. Check NTP for time sync…
It uses Tasmota integration.
I have not other ideas what to do and what can be the cause of it.