Actually I just noticed that from time to time all the item states are set to null instead of actual values. After a couple of minutes everything goes back to normal/actual values.
I added the thermostat with the homeassistant discovery (OH autodiscovery is set to ON).
For all the other thermostats I own I’ve always set up the things as generic mqtt things. I noticed that sometimes the messages received from the thermostats come in empty (no measurements) so I added a second transform step to get rid of error messages in the logs like so: REGEX:(.batt.)∩JSONPATH:$.batt
I assume that these empty messages that the gateway receives from time to time result in null states, is that possible?