Certainly seems like an issue with these Amazon playlists, and the ability of the speakers to reach out to ‘get’ the data properly. Where is the music stored?
You may need something as simple as a network refresh. Unplug all of your Sonos devices from power. Then reboot your router. Wait two minutes, then plug your Sonos devices back in to the power. Wait another two minutes, then open your controller and check for any updates, and apply them as needed. Finally, test your playlists, to see if the issue is resolved.
Since Sonos itself doesn’t ‘store’ any music, but plays whatever it is handed by external sources (including playlists), it’s possible that the issue ultimately lies with Amazon, especially if the data is stored there. The above procedure should clean up any chances it is locally caused, but in case it doesn’t, and the issue continues, I would recommend that you submit a system diagnostic within 10 minutes of experiencing this problem, and call Sonos Support to discuss it. Don’t post the resulting diagnostic number here, their lawyers get sensitive about GDPR.
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 Support staff, they have tools at their disposal that will allow them to give you advice specific to your network and Sonos system