Smart Radiator Thermostat displays two groups of dots instead of temperature

One of my Smart Radiator Thermostats displays two groups of four dots that move outwards from the radiator when trying to set temperature. This is after a battery re-install until the final "three blobs" display after seeking the mechanical endpoints, at which point the two groups of dots are displayed instead of the temperature setting.

Any suggestions on what is wrong here?

Also, is there a chart of possible display errors anywhere?