ATEM Production Studio 4K High Pitch Buzz Audio Out

We are working on a tech install for our new church building and ran into an issue with our ATEM Production Studio 4K. We are running pro presenter in a MacBook via HDMI to the ATEM in our control room. When we plug in the XLR to send mono audio back to our soundboard (audio output #2), we get the audio, but also a high pitch buzz. Audio output #1 is just a buzz.

Any idea what is causing this? We ran out of time Friday night and weren't allowed to keep our equipment in for much longer (contractor, inspections etc.). One thought after the fact was maybe we need to turn off the lights in our control room. We can run audio back to the soundboard no problem, but when we plug into the ATEM that is when the high pitch buzz shows up.

Have you checked for ground loops? They can be nasty thing, low or high pitch noise.. You might want to check the outputs with a simple audio board connected directly in the same room with the power connected to the same source.. And then check if the audio is still going weird with a headphone..