ProSafe Manage Switch Power Bump When Unplugging Second Power Supply

Hello,

I am using multiple Stacks of M4300-52G-PoE+ ProSAFE 48-port 1G PoE+ and 2-port 10GBASE-T and 2-port 10G SFP+ (was unable to find the model in the drop down above).

We run the Stack switches with dual power supplies that are connected to 2 APC UPS's, all switches in the stack have one power supply going to each UPS. We recently swapped out a UPS for a new UPS and once we pulled the plug from the switches out of the older UPS all of our POE ShoreTel phones dropped connectivity as well as all the computers plugged into each of Netgear Switches.

At first I thought this was an odd coincidence, but tired some testing. I unplugged one of the powers supplies from one of the UPS's (verified the second power supply was fully plugged into the other UPS.) and the same thing happened, all phones and computers plugged into the one switch I unplugged from the UPS dropped network connectivity. tried it on the second switch in the stack and exact same thing... all phone and computers plugged into that switch bounced as well. 

My fear is that basically these redundant power supplies are not doing what they should... I am under the impression that if the switch loses one power supply it should still keep all devices connected with no interuptions what so ever. 

The firmware on the switches is 12.0.4.8 and boot verison is B1.0.0.11. Attached is a screen shot of the Device Status.