If it’s a regular interval, maybe check the routers DHCP renewal time to see if it coincides. However if you can’t get to the root cause, then it maybe best to reproduce the issue(s) seen and then immediately submit a Sonos system diagnostic report from within the Sonos App, note it’s reference and contact/chat with Sonos Support Staff via this LINK and see what the Staff can perhaps suggest to help you to resolve the matter.

Just to also add, I’m not seeing the issue with my Home Sonos setup, so it’s possibly something that’s local.

I tride already so much. Also had contact with servicedesk. They advised me to startup the playbar to factorystand. This takes a lot of new configurations everytime. I did that already several times and then it works fine for a couple of ours. The interval is not the same every time and fluctuaids very much. I starded up everything in my network many times and looked for connections in my router on strange items, but found nothing. The problem stays and sometimes it is gone for a few ours. It's by now a hopeless problem and much frustration.

Also sended diagnostic content from my system to serviecdesk many times.

This is mainly a community of Sonos users - you are perhaps best to go back to Sonos Support and see if they can perhaps assist you further. I’d speak to them over the phone. See link to contact the Staff:

https://support.sonos.com/s/contact