Sharing this in case others experience something similar. And who knows, maybe someone knows a solution :-).
I run core-2021.10.3 Home Assistant OS on an RPi4 . I am using the DSMR integration, DSMR Slimme Meter - Home Assistant . I’m using the serial connection, with a P1-cable running between my smart meter and the RPi4.
I find infrequently suddenly data stops showing up in HA, the integrations entities reporting to be unavailable. Since starting to see this and trying to solve it, i have ended up with just deleting the integration if i notice it happened again, adding it again, and everything will be fine again. I would love to know why the integration infrequently stops receiving/reporting data.
I recently added another device to my config that needs access to the P1 port, so i have added a P1 splitter. Afaik, this has not influenced the described behaviour: the integration ‘not working’ happened both before and after me adding a splitter. But i notice the other device keeps reporting data from the P1 port, so i think it is not the P1 port/smart meter that is the problem, and assume it has to do with something on the RPi/HA-side.