I agree. I really don't think it's the temperature in the closet, but that's the only factor that I can see that makes this switch any different from our other closets.
The switch is running AOS 7.3.1.
This switch is also only half populated. It is a 48 port switch, we are using 26 ports at this time.
All of the PoE phones are stationary and they are rarely unplugged, so the amount of PoE draw should be relatively steady.
It is possible that there is greater traffic at times, this is an administrative floor where not everyone is Always in the office, so that could play a role in why this is hard to diagnose.
The counters available on the GUI show Zero events. Airwave also does not indicate an issue.
This switch is a connection point between our two stacks though. We have a fiber link between a stack with 3 switches and this stack. All traffic comes in on a single vlan as it is all AP-93Hs. The stack connected to this is our 'dorms'.