I just added over 500 songs from both my library and Amazon Music to my queue and hit shuffle multiple times, and they shuffled and reshuffled just fine.  So whatever is happening on your system is not happening everywhere. 

I just built a Queue of 1006 SPOTIFY tracks and have no trouble shuffling. Do you have a local music library? If so, how many tracks are in your library. A large library index might tie up enough player memory to limit the size of Queue that can be managed.

Next I added a bunch of AMAZON tracks to bring the total up to 2148 and still have no trouble shuffling.

Is this an S1 or S2 system? Older S1 only players have less memory than the newer units.

Thanks for weighing in, folks. I’ve encountered this with Amazon Music Unlimited first, and now with a new Spotify Premium subscription confirming it is a Sonos issue not that of the music services. I have thousands of songs in my library in the cloud (not downloaded locally). Most noteworthy is the several community posts over the last 3 years on this same exact experience and conclusion. So looking for a Sonos fix, not a labor intensive workaround. 

My entire system is between 1.5 years and 3 months old. 

…and as others reported no issues with the monster playlist shuffle when not using Sonos app. 

Do you have large SONOS Playlists? These are stored locally in the players and could result in some RAM starvation.

Your best bet would be to submit a diagnostic, log the confirmation number, and contact SONOS phone support. Only SONOS staff has access to the diagnostic data. You can post the confirmation here in case a staff member notices this thread.

FWIW, I’m still playing from that shuffled 2148 track Queue without incident.

Thanks buzz. I’ve hit the wall with Sonia support on this 2-3 times already. My library is all within the native Amazon and Spotify apps, then accessed via the Sonos app. 
 

Btw, where in Amazon or Spotify can I locate the track count? Best I could locate is 229 hrs of music in said Spotify playlist. On the Amazon side I could have over 10k songs. 

Amazon Music limit the number of tracks that can be queued at one time to 500 tracks maximum, so there is nothing for Sonos to fix.

I'm shuffling a playlist of 900 odd songs on Sonos via Amazon music and the same 50 or so songs play again and again. Drives me nuts 

If you leave the queue, then come back to it, the queue will start over again, which will cause the same songs to play every time.  To prevent this, click the shuffle icon off then back on and the queue will reshuffle. 

Would that be the shuffle button on Sonos app or Amazon app?

Thank you 

The Sonos app.  If you are playing from the Amazon app and the songs keep repeating, that’s an Amazon problem, not Sonos.

Thank you, I've tried steaming Amazon from Sonos app (this only accesses 500 of the 900 songs) and directly from Amazon through Sonos (this allows all tracks but still only shuffles a select few)

I'll try you suggestion.

Do you know if shuffle works better via apple music, Spotify or any other services? 

Thank you for taking the time to answer, I really appreciate it 

I only have Amazon Music, so I can’t answer about Apple or Spotify.