Do the SONOS units have WiFi credentials? Unless you have a ROAM or MOVE, I’d remove WiFi credentials from the SONOS units. Some of the access points provide a LAN through port. I’ve had storms if I use this port for a SONOS player. Maybe this was a “feature” of one particular Ubiquiti firmware release, but I regretted that update. How are the switches interconnected? Pure speculation on my part, but if you are using SFP, might you need to specifically enable STP on those ports?

I run full ubiquity stack as well and a similarly complicated network. I had a lot of issues with network stoms… I think buzz is right, you need to visit the post settings on the managed swtiches.

How does Sonos hold up on that large of an installation?

I currently have 3 amps, 2 arcs, 1 port, 6, one’s, and a sub… but was thinking of adding 8 more amps and maybe a sub or two.

on my previous comment, I meant port setting not post.

Thank you for all the feedback and suggestions.  I ended up wiring every Sonos device and disabling the WiFi on every device.  I made no changes to the network and it has not only been rock solid the Sonos and network as a whole is more responsive and reliable.  Going on 4 days with no hiccups.

I have maxed out some Sonos systems with 32 devices with no issues but this was a very unique and unconventional property and system.  Just wanted to share the solution that worked for me.

If all or most of the units are wired, I would not expect any issues. Supporting a system this large wirelessly might not be reliable. A lot depends on wireless topology and local interference/clutter.