I recently bought an Omnitronic IEM-1000 set (complete with transmitter and bodypack-receiver), but have run into an issue. My mixer only has mono output, so I am simply feeding that to the right input of the transmitter, which I have set to mono mode in accordance with the manual. 
However, when I turn on the bodypack, the sound seems to be sent in stereo, with the left channel being much lower in volume than the right channel. At first I thought this to be an issue with the earphones I had connected to the bodypack, but having tested with three different pairs of earphones I figured that was not the problem. Today I tested the transmitter without turning on the bodypack, and as it turns out, the display on the transmitter shows different volume levels on the left and the right channel (despite receiving only a single mono input). 
There is no balancer on the transmitter itself that could affect this (all balancing is done on the bodypack, and above issue occurs when left and right channel are in balance. They seem to first be in balance when the volume is shifted so far left that both sides are barely audible, which is obviously not optimal).
I have also tested connecting a stereo plug to the transmitter instead, but the result was the same. I have tested with different sources (from my PC, from my phone and from my mixer) and the same problem occurs. It works fine when connecting an actual stereo signal, and strangely connecting stereo and setting the transmitter to mono seems to work just fine aswell. These "hacks" are obviously not the intended way to solve the issue, though. So I was wondering if anyone here had an idea as to what the issue might be?
Update as of 27/09-2022
I have acquired a new set of the Omnitronic IEM-1000, and the problem persists. Thus, it seems to be an issue with the model itself, but I can find absolutely nothing elsewhere on the internet that indicates that this behaviour is expected (or other users facing the same problem)
