Sounds odd.  

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, they 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.

What does “ edit it and save it again” mean? Sonos playlists need unique names, or are you saving it as a Favorite? This would explain why your changes “stuck”, as you edited the playlist and the favorite points to that. (Also Faves have more arcane rules about name collisions).

Err…. it means you edit a Sonos playlist and try to save the changes 

It’s always worked in the past, I first saw this behavior several months ago but I couldn’t pinpoint when it started to a specific date.

Do you mean Save Queue, or Add Track to Sonos Playlist, or something else?

I can’t remember what the limit is on the number of Sonos playlists, I know there is a surprisingly small limit on Favorites though.