Cisco Switches :: SF200 Witches Will Simply Freeze / Blocking All Traffic Flow

We have been deploying Cisco SF200-24P switches for our systems for over a year now. They connect to a Cisco 881 router. In many cases we are also deploying Cisco AP541s.Over the last few months, on an intermittent basis, the switches will simply freeze, blocking all traffic flow. The power LED also goes dark. It appears the switch has frozen. The only thing that seems to revive the switch is a hard reboot by pulling the power cord. In the last couple of weeks, one site in particular has gone down a handful of times. That client of our is fed up. Our patience is running thin too.
 
I cannot see any indications in the logs to any event that might give a clue as to the problem. We definitely see this problem with the 1.2.7.76 firmware and the 1.2.9.44 (latest as of typing this). Not sure if with earlier 1.1.2 firmware.Without a fix, we likely will have to change switches and possibly vendors as we need a reliable switch.I see some vague references to a similar problem. And one reference to a SG300 series having what sounds like the same issue.