Without any information to look hone in on, it’s hard to tell what the issue could be. It could range from overheating, to wifi interference , to duplicate IP addresses. 

Have you called Sonos Support directly to discuss it?

When you speak directly to the phone folks, they have tools at their disposal that will allow them to give you advice specific to your network and Sonos system.

yeah this issue has reappeared for me as well….
 

I’m curious as to what Support said, when you called them with this issue.