Thermostat missing attributes

Hi
In my home-assistant.log exceptions like this shows up a few times after restarting (this is the first occurrence):
2019-05-12 21:29:57 ERROR (MainThread) [homeassistant.components.websocket_api.http.connection.139945458425192] must contain one of temperature, target_temp_high, target_temp_low.
Traceback (most recent call last):
File “/usr/local/lib/python3.7/site-packages/voluptuous/schema_builder.py”, line 267, in call
return self._compiled([], data)
File “/usr/local/lib/python3.7/site-packages/voluptuous/validators.py”, line 204, in _run
return self._exec(self._compiled, value, path)
File “/usr/local/lib/python3.7/site-packages/voluptuous/validators.py”, line 286, in _exec
raise e if self.msg is None else AllInvalid(self.msg, path=path)
I’m not able to find out which device this is.
I’ve checked every thermostat and device I have that report temperature. They all seem to work just fine.
Any help on where to start searching?
hassio 0.92.2 on intel nuc debian 9.
Helge