Homepod mini 16.3 temperature readings get stuck / don't get updated

I'm experiencing a problem that the homepod mini temperature readings get stuck / dont get udpated for a long time. For example when I open a window and turn off heating so the room gets colder really quick. Before the Homepod says, let's say 20°C. After about 1 to 2 hours (!) the homepod still reports 20°C while two other thermometers (one digital and one liquid) showed about 15°C. This happens repeatedly with all of my 3 minis.

Here's what I tried so far ( Homepod on 16.3 final, never had any Beta oder RC releases):

• restart the Homepod : after calibrating it shows an updated value and seem to work for a while until it gets stuck again.
• disconnect power source for a while, then reattach
• factory reset of all Homepods
• factory reset + delete my home from the Home App and starting from scratch

What i observe:

• I need to do further observations, but it seems the temperature gets updated more likely when there is any kind of activity/interaction with the homepod like playing music, near U1-chip activity or Siri interaction.
• humidity readings don't seem to be affected (not completely sure about this)

Any Ideas? Maybe some deep sleep mode or something is preventing temperature sensor updates?