We upgraded all the sites at our affected client with this firmware as well and are removing scheduled reboots to test over the next month.  ... View more

I don't know if this was intentional but it works in the new version. If you go to Wireless - Access Control there's a link in the upper right hand corner that says 'Try new version' - it will take you to the new SSID page and it works for us there.  ... View more

I am having the exact same problem with a client of mine running MR52s. We are waiting on the next release for later this month. They say they hope to have a fix for this. 28.5 seems to be running better these days. We stayed on 27.7.1 for a while just to be sure, but recently upgraded more sites to 28.5. Fingers crossed.  ... View more