Hi,
in my setup I used Future Drummer for Drums, AUM hosting Pure Piano for the melody sound and Riffer in standalone mode for the melody notes.
There is a reason why I do not host Riffer inside AUM - I tried Riffer running standalone to overcome a strange behavior running it as an Auv3 MIDI FX in Logic Pro.
So this setup is for an easy reproduction of the problem, probably a bug.
There are 3 peers in this Ableton Link session, and only if I run Riffer in the foreground and press its play button I get all peers starting.
Starting the Ableton Link Session in AUM or in Future Drummer will always kick off Future Drummer, but Riffer does not start.
If you look at the screen shot of Future Drummer it looks like that Riffer has left the Ableton Link session as there is only 1 peer visible, which is AUM.
