Error "Invalid option for ..." in HA core logs

I am observing following logs in HA Core logs:

2022-01-26 20:32:15 ERROR (MainThread) [homeassistant.components.mqtt.select] Invalid option for select.office_e6_sensor_temperature_unit_convert: '°C' (valid options: ['celsius', 'fahrenheit'])

These are some Nous E6 temp/humidity sensors (zigbee tuya) connected over Zigbee2MQTT. All of them report the same thing.
They work fine by itself, it is just those logs. I am unsure if this is Z2MQTT issue (I asked on github there too) or HA.
When I go to Z2MQTT panel, device, and select “celsius”, they actually flip to Fahrenheit (on display)

in HA, if I find the device and select “Temperature unit convert” and pick Celsius, it also flips to Fahrenheit, + I get some edditional warning logs:

022-01-26 20:37:12 ERROR (MainThread) [homeassistant.components.mqtt.select] Invalid option for select.office_e6_sensor_temperature_unit_convert: '' (valid options: ['celsius', 'fahrenheit'])
2022-01-26 20:37:12 WARNING (MainThread) [homeassistant.helpers.template] Template variable warning: 'dict object' has no attribute 'temperature_unit_convert' when rendering '{{ value_json.temperature_unit_convert }}'

Any idea how to stop these?