MKR Explore IoT Kit reading Temperature with Case

Hello everyone,

I´m new here and I hope i don´t violate the board rules with this post.

I could not find a specific topic regarding the MKR Explore IoT Kit. I hope the marked topics are correct, since they are the same components.

While working on the lessons I noticed a difference between the temperature readings and I think they might be a little bit off.

With no case and supply via USB, the temperature is nearly 24°C.
With case and supply via battery, the temperature is around 29°C.
With case and supply via USB, the temperature is around 30°C
With case, battery and charging via USB, the temperatue is around 30°C.
When the case is off, the temperature readings are immediatly dropping.

I am aware of higher temperatue while charging the battery because of higher power consumption.

But whats with the case? It seems the case has an impact on the readings. Is there a known offset?
Can I affect the readings? For example turning of the backlight of the Display, or other things?
Or is it generally a bad idea to use the intern temperature sensor while the case is mounted?

Thank you!