If I read this correctly, the receiver is powered locally. Most HDBT matrices are POH for a number of reasons. Besides convenience, most of the time the receiver and TV would be on an outlet on a different phase than the rack. If there is something noisy or taking a big power draw that might be using much of the available amps creating a surge or brown out. I'm not a sparky but we have pretty much seen it all when it comes to tech support.

Sydinstaller also brings up another enemy of HDBT; the keystone or patch panel. How close is the CAT cable routed to a jbox or flourescent lighting? EMI/RFI can also cause intermittent issues like this. Hopefully someone didn't nick the cable jacket somewhere along the line.

One thing to try would be to run a new CAT cable externally from the rack to the TV with an HDBT kit that is POE. It might help narrow down if you truly have a cable issue.

Good luck