2 way midi possible with HX FX and Fractal FM3?

[spankygtr]

I configured the HX Effects to control the FM3. No problem. But I wanted to do something interesting with the fm3's 3 footswitches. I thought maybe I could use that as an alternative way to trigger individual effects on the hx. So I set the two units on different midi channels. I was able to switch an effect on or off (on the HX) from the fm3, But after doing so, the HX was frozen, would not switch to a different patch, until I unplugged the incoming MIDI cable. Is this type of two-way communication between the devices not possible?