My Roland TD-10 is controlling the main hihat triggering. I’ve tried it two ways-
 With the second hihat pad (actually just a regular cymbal trigger) in an AUX input on the TD-10 and just triggering bow/edge on various MIDI notes, ones not associated with any hihat
With the second hihat plugged into one of my eDrumin triggers, again with various MIDI notes
If I assign the second hat pad to any other instrument (tom, cymbal, snare etc) it works fine, so it doesn’t appear to be a trigger modules issue.
Even if I don’t assign any trigger to the second hihat, it still seems to “break” the main hihat.