Hi, i think that does not work this way, i replaced my matrix with a switch (and do the magic with OSC{} receive). It is maybe usefull if you have different types in your matrix...
You could tweak the props property, there u could use $ as index (e.g. something like here [SOLVED] Button Matrix not listening on address - #3 by benjaminauer)
If you experience problems i think you should investigate in a matrix with cloned objects (did not try that one).
Hope this helps..