Microphone input forced limiter - Behringer UMC404HD interface

I use the Behringer UMC404HD interface to record with a single channel (mono) and the program limits the input volume to -12, if I change it to 2 channels (stereo) the problem does not occur. The fault is in the software, I did several tests increasing the volume of the system microphone in Linux Ubuntu as well as increasing the volume of the interface and the limiter remains activated in Audacity. I have recently started using audacity on both operating systems (windows and linux ubuntu) unfortunately in Ubuntu I have had this problem. I count on your support.

It’s not actually limiting. It’s lowering the volume. The clipping indicators should still be telling the “truth”.

It’s lowering the volume (in the digital domain) so that in mono you don’t go over 0dB with all 4 inputs summed together.

…This is the 1st time I’ve heard about it with a 4-channel interface. With a stereo interface the signal is cut in half (-6dB).

It only happens with this interface in mono mode. I can record in stereo on a single channel and then separate the audio in stereo to mono but it shouldn’t be correct. I already change all the possible configurations but unfortunately nothing more can be done from the software.
Captura desde 2024-03-25 10-50-50

As you can see in stereo it doesn’t happen, there is no forced limiter.
Captura desde 2024-03-25 10-56-59