Tado Smart AC Controller won’t turn off AC at desired temp.

I have had a single smart AC controller (V3) running for about a month on a 5kw Mitsubishi Heavy split ac unit. Working absolutely fine in heat mode, I set a scheduled temperature and it heats the room to that temp and then goes into idle mode until the temp drops when it will kick back in.

With the success, I ordered 3 more smart ac controls for the other rooms. These are still MHI units but smaller 2.5kw versions.

On these units the smart ac will not set the units to idle when target temp is reached. Instead they just keep on heating or cooling indefinitely. This morning I woke up and my office was 29 degrees C(!) despite setting it to 20.

No issues with connection or line of site, commands are getting through fine and the units beep as if accepting changes.

Any ideas?