The Raspberry Pi is connected via LAN the Squeezebox Radio is connected via WiFi. Normally i only use Apple Music for streaming/listen to music but i still have my old mp3 archive, so i just copied some mp3s over to the LMS music directory on the RaspberryPi (/home/pi/music) and played them on the Squeezebox. I had no pauses with this!
At the moment it seems that the pauses occur only when streaming music from my iPhone to the Squeezebox using LMS (Shairtunes)! But it also seems that some songs have less pauses, but i am not sure about that!
I also stream to my regular Airplay speaker in my living room (which is also connected via WiFi to my network) from the iPhone, but this works without pauses!