load a simple midi-clip, route the output to another audio-track. audio-track is monitor in. on a return-track A you put a boosted saturator, an eq8 with a peak in the midrange plus a simple delay, feedback 0%. now turn up the send A in the audio-track and try to turn up the send A in the return track. nothing happens, no feedback! the send A in the return is grayed out.
strange......