To be fair, if you made a change like that and didn't change the harness to make it physically incompatible, that's not the user's fault. It might not be your fault either, but it most assuredly is somebody's fault.
In this case there are only so many combinations of MIL-DTL-22992 out there.
It wasn't even our harness. No idea where it came from. Serno didn't register, wasn't shipped with the device and wasn't approved (I know as I wrote the asset tracking software).
I still reckon they lost the official harness, rigged this one up and FUBARed it but the moment you point a finger, the professional cockroaches scurry away.