There are two main potentials here.

The first is simple wifi interference , which equally can affect SonosNet (wired mode) or a connection to your WiFi directly. Due to the variability of WiFi interference, the clock speed measured at any disparate time doesn’t really matter. And unfortunately, not all wifi interference comes from within your home. 

The second possibility is a duplicate IP address, which can rear its head after a software update by Sonos, due to the soft reboot Sonos does to each device to load the new software. If the router is in a confused state, it can hand out duplicate IP addresses to any device, including, and most sensitively, the Sonos. I’d recommend a simple network refresh, by unplugging all Sonos devices from power, then performing a reboot of your router. Once the router comes back up, plug back in your Sonos devices, and they should receive fresh IP addresses from the router. 

However, if neither of those solutions work, I would recommend that you submit a system diagnostic within 10 minutes of experiencing a dropout, and call Sonos Support to discuss it, or post the diagnostic number here for a Community Moderator to pick up.

There may be information included in the diagnostic that will help Sonos pinpoint the issue and help you find a solution.

When you speak directly to the phone folks, there are more options available beyond just the diagnostic analysis. 

Thanks much for that thoughtful reply… unfortunately those are all steps I’ve taken in the recent past without any luck.

I do plan to repeat them soon when I have a chance just to check the boxes on Sonos’ request to do those from the person I talked to on the phone.

This diag was run just about a minute after one of the most recent dropouts : 827926870