Hi @FreddyO, welcome to the Sonos Community!
With certain older legacy Sonos components such as the Play:5 Gen 1, it's possible that you may experience audio interruptions from certain music sources, Spotify being one of them. While this doesn’t happen on all legacy products, the diagnostics shows that this is what’s happening to one of your Play:5s.
There isn’t a lot of troubleshooting we can do for this issue on the community, but I’d recommend trying to wire the left Play:5 directly to your router via an Ethernet cable to see if that will mitigate the issue. If that doesn’t help, then I’d suggest you call our support team for further assistance.
I hope this information helps!