Overbridge 2.0 with Digitone - Audio/Midi issue?

I’ve got a Digitone connected to Ableton through Overbridge 2.0, with a Keystep running Midi into the DT, and the DT running Midi out to a Drumbrute and a Prophet Rev-2. For some reason, when I’m monitoring through Overbridge in Live and I’m trying to play/sequence the DT’s Midi channels, T1 plays in unison. However, when monitoring thru Line-ins, this doesn’t seem to be a problem.

ie, if I sequence a bunch of C3s on MIDI 1 (to play the Drumbrute’s kick), I also hear a bunch of C3s from whatever is on T1. Muting on the DT seems to make no difference. This has the additional effect of the DT ignoring anything I sequence on T1, instead playing whatever I sequenced on Midi 1.

Sorry for the Primer-like convolutedness of this post, but I’m kinda stuck here. Any clue what I should do? I would just run everything into separate line-ins, but my interface only has two of them, so I kinda need to use those for the Prophet, and the DT’s line-in through Overbridge to record the Brute.