This is really a pain. I've tested all major DAWs and Studio One, my daily driver, has the worst support for the Osmose.
In addition to Studio One not being compatible with the EaganMatrix, I am having problems recording and playing back standard MPE. (Not MPE+)
The issue has to do with the simplification that Studio One does to MIDI control points. When you wiggle a key for pitch shifting, you can see that the recording is capturing many control points. But when you stop recording, Studio One simplifies the number of points too much. It leaves too few points, and when you play it back, it sounds completely different.
I suspect it has to do with a variation of +-1 semitone being interpreted as something flat, and it oversimplifies. But I haven't been able to change the settings to make it understand that 1 semitone is actually significant.