My Sigma studio version 3.14 Buid 1 Rev 1675 (11/28/2016)
I use ADAU1452. In my case NxM Mixer expand to 25in x 25 out
NxM Mixer does not work the first output. Others outputs works OK.
Maybe module NxM Mixer has misnamed inputs and outputs. Left side (inputs) start as pin1, pin2 etc.. Right side (outputs) start as pin0, pin26 etc...