I've yet to talk to TAC about this as I know they're going to want to test and it's a little hard to test in a live environment but here's my story. Last Friday I had to come into work for a couple of CoW's not connecting and it was very odd. So in troubleshooting I was dinking around with the 4404 controller (5.2.178 code) for that building and looking at settings and made a few changes I'm (sorry not sure what at the time but it was in the WLAN, though nothing related I can guarantee you as you'd have to be an idiot) applied my changes and then I started getting yelled at that all of our carts were dropping connection. They'd attempt to connect but would end up with a Windows error of 'Unable to obtain IP address blah blah'. So I thought it was something to do with DHCP or DHCP settings in the controller. I ended up just shutting that controller down as I couldn't figure it out and was under pressure to get ti back up. The AP's roamed over to my other 4404's and everything worked fine. I left it until today as I was scheduled to go out of town. Well, my two CoW's (carts) were still having problems this morning and I was to look at again.. again, I started doing some testing and holy crap, the same thing happened with my 4404 on 5.2.178 but Controller 2. I took my time this time and looked at the logs and basically was rejecting my authentication so on a whim I decided to copy back in my PSK to the WLAN and walla... they all came back up. AGAIN, nothing was EVER changed with the PSK previously. So what the hell!? Is this a documented bug somewhere? I haven't seen it at all but this is pretty major in my opinion. BTW, WCS version is 126.96.36.199.