Two things, firstly, check your rack voltage. This sounds a LOT like you are getting some low voltages on the rack.
It could be either a bad PSU or it could be noise on the mains and the PSU is not able to filter it and is causing the rack to glitch. (This possibility is going to tough to track down, but I have had this exact issue with some racks at the hospital a few years back - we installed a small double conversion (this bit is important) UPS to test if the mains were the problem, they were).
You need to measure between 5.0 and 5.1 volts between the input terminal (-ve) and the far end of D2 (+ve) on the SNAP rack.
After doing this, and making note of it over a few hours, if it looks rock solid, give support an email and get them to start working the issue. firstname.lastname@example.org