Can you describe your actual system, detail the local network setup (make/model router, channels/channel-width in use, switch STP settings etc.) and the audio source/format you’re using and perhaps then some suggestions can be made.

A lot more information is really needed here for anyone to be able to assist you.

As Ken said, more info needed.

You might want to wait for the problem again and within a few minutes submit a diagnostic, you can post the number or call Sonos support directly to have it looked at.

Perhaps a better way to phrase this is I’m missing a channel. I noticed it while listening to California Dreaming on vinyl. Originally it led me to lack faith in my aux cord from turntable to my Five speaker, only to find the same issue when streaming from Spotify. 

Can you perhaps provide details of your setup, as you may perhaps have more than one issue here. Are devices wired to the LAN, or using the local WiFi - which band/channels are you using? If using WiFi have you tried a different WiFi channel. Maybe select a fixed non-overlapping channel such as 1, 6 or 11 or just see if wiring the speaker makes any difference to the Spotify stream. For the line-in audio from the TT, maybe try compressing the line-in audio (In the Sonos App goto Settings/System/Audio Compression) and just see if that quickly resolves your issue. 

Be sure to check silly things such as a mechanical issue with the Line-In plug not being fully seated, or the speaker’s Balance adjustment gone astray.