This is a problem on MG4 Trophy with heat pump. At least some of us are affected by this.
I only get it after having charged, so for my car I’ve found a pattern.
Also, as an extra step, I run several updates of “Vehicle Status” in iSmart app before initiating the pre-heating. That’s where I see the Interior temperature and Exterior temperature.
First run, interior 18° C, Exterior -4° C. Clearly not right.
Every run, it drops a couple degrees on the interior, and after several refresh it’s down to reasonable numbers.
Then I start the pre-heating.
Sensors are clearly not working as expected, and may be a reason why it fails on generating heat from the heat pump, don’t know.