HomePod Mini pauzes itself after 2 minutes (version 18.4.1)

Hi all, I bought a third HomePod Mini and placed it in my bedroom as separate device (the other two in my living room are a stereo pair). I installed and configured it. Also did the last update to the version 18.4.1.

I want to play radio station via intunes and when I ask for it to Siri it finds it and starts playing the radiostation but every time after about 2 minutes it puts itself on pause for some reason.

I already deactivated automatisation in case it was the issue but no difference. I also checked if the wifi connection is ok and it is. (it would also be weird that every time I ask Siri to play the radio station it is well connected and finds it to have the connection then always go away two minutes later.)

What could be the solution to this issue?