A few observations...
First, if you are seeing audio input with nothing connected to the XLR inputs, then something is wrong with your ATEM. If you see input/noise with an XLR plugged in, does it go away when you unplug the cable from the ATEM? If so your problem isn't in the ATEM, but further upstream. Grounding issues are common in analog audio and can cause what is described. Fixing this requires an inline isolation transformer like the Sescom IL-19, or correcting the ground fault which is usually related to where you have everything plugged into power. All audio/video devices should be powered from the same source.
Secondly, the issue of repeating this fault by too much input level. I'm not disputing what you guys report, but I cannot reproduce this on any of my ATEM units (1ME4k, 2ME, 2ME4k, 4ME4k-sorry I don't use TVS series products). I am inputting audio level of about +33dBM, the most I can get out of any of my audio gear, and the top of my test meter LOL. While this results in a highly distorted audio in the ATEM mixer, as soon as I reduce the level to normal the ATEM sounds fine. Can't say that I think this is any kind of "bug" but certainly makes me wonder what you guys are putting in
BTW, my 2ME's are running v6.9, my 1ME4k v7.5.2, and my 2/4ME4k's are both running v8.2.2. Again, I don't see any extraneous noise, and am not losing any input audio.
I suggest those of you with this issue need to contact BMD support, I admit this could be an issue specific to the TVS series of ATEM. Wish I had one to test for you...