I have recently replaced my R510 with an R550, I did connect the new R550 so the config could be transferred before I disconnected the R510.
Now my Sonos-Players need a couple of hours until all of them can be seen in the apps. Restarting Sonos players does not help. On some devices they are faster, on some slower. When the Sonos devices are unavailable in the app, i can see the IPs of some devices as "connected" in the unleashed system. If I restart a Sonos which is not connected it does not connected, it does not connect after ther restart either. If the sonos are finally connected, after every restart of the AP the problem is back.
If I reset the R510 and bring it back online, then switch the R550 off, everything works smooth.
I am aware what Ruckus recommends https://support.ruckuswireless.com/articles/000006140
However this setting doesn't seem to be necessary in my case on the R510 and does not fix the problem on the R550