Elektron Musical Instruments

hi,
i stumbled across some strange thing in the mono and cant figure out if its a bug or a 
feature.
try it for yourself.

in a kit that uses a FX machine change the FX machine into an instrument.
now when i record some notes for that track it sounds like the sound is intermodulating 
with the sound of the tracks that were sent to the fx machine in the original kit settings.
When i play live i get a stack of the tracks that were sent to the FX track plus the 
instrument that replaced the FX.
Cant find a way to get rid of that.

is it just me?

Hans