Unable to set thermostat temperature exactly, keeps changing


I’ve been using a CT100 Z-Wave thermostat for the last 4 or 5 years (at least) and never had any issue with it. Recently, it started acting up a little bit. I am now unable to set it to the exact temperature I wish, it keeps changing a couple decimal lower than what I set it to

As an example, if I set it to 23C, it will change to 22.8 a fraction of a second later. I set it to 23.8C, it changes to 23.3C. 24.3C, it goes to 23.9C.

Could this be caused by an internal conversion from C to F?
23.9C = 75.02F (75F = 23.888C, rounded to 23.9C)
23.3C = 73.94F (74F = 23.333C, rounded to 23.3C)

Any idea what could be causing this?