I've followed posts here, there was no solution.
And no support from Sonos.
I've found out that it happens when streaming from Spotify or another service.
However
If you play via Sonos app S1, downloaded songs that are on your device, it does not happen, and the intermittent one speaker cut out, is not happening at all
What does this mean?
Service streaming issues?
Any thoughts appreciated 
Do you have a Bridge, your profile equipment list is empty, try unplugging it and if necessary run a temporary Ethernet to one of the Play 5s.
What format and resolution are your local music files?
The solution would appear to be grouping the Play:5s with another Sonos speaker, but that’s not much help if you don’t have other devices.
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