At 96 kHz with a 48k frame.

Using two Madi-AES boxes. There are 32 channels maximum. The first box uses MADI channels 1-8 and the second box uses MADI channel 9-16. The first box intercepts MADI channels 1-8 and sends channels 9-32 on to the second box.

Listening to headphones on the first box, when listening to MADI channel 32 I have sound, the music which I am reproducing on MADI channels 1-2. The second box does not have sound on channel 32. Totalmix does NOT show any signal on channel 32 as well. So there is a mystery source of sound on MADI channel 32. And only audible on the first box. Both boxes are in AUTO routing mode with ADC turned on. Except when I monitor with headphones, which requires getting out of AUT routing, but I have the manual routing set the same as AUTO would do: AES in 1-8 (9-16) to MADI out 1-8 (9-16).  MADI in 1-8 (9-16) going to AES out 1-8 (9-16). And passthrough from box 1 to box 2 on 17-32 and 17-32 back to the computer from box 2.

I've traced it so far to a patch that I have in my Z-Sys router. I routinely patch MADI OUT 1-2 back into MADI IN 1-2 using an AES/EBU patch in my Z sys router. Sometimes I need that for processing reasons.

If I disconnect the patch sending MADI out 1-2 into MADI in 1-2, the sound on channel 32 disappears. So it appears that sending signal into MADI 1-2 ends up on channel 32 monitor in the first box but does not show up on channel 32 in Total mix metering.