So I've been in contact with both KPA support and I sent my unit to the dealer for testing. Upon testing they found nothing wrong with the unit, and I got it back yesterday from the dealer and decided not to RMA it like originally planned. I've tested all outlets in my apartments, checking turned off lights and made sure there's no EMI issues. This buzzing comes no matter what I do, even if I only use headphones and no other cables connected.
The strange thing here is that the buzzing disappears when I use a wireless transmitter. I can't figure out what this buzz is coming from, and it's driving me crazy.. It happens on all guitars I have no matter the cables used. As long as I am using a physical cable, the buzzing comes on.