Ok, the fact that its 2 semitones, is roughly the same interval as 44khz/48khz. So I think what you experience is that MG somehow think that you run at a samplerate of 44khz but AUM is actually running 48kz (or the other way around).
Please try to change the samplerate, and also try closing the apps and replugging your interface - maybe you also have some other audio apps running in the background that dictates the samplerate.
Its not something I can reproduce here, for now at least.
Edit: another idea - could it be related to pitch bend? Maybe the “pitch wheel” is somehow stuck at zero which would be 2 semitones on most synth… Please try to disable pitch bend in MG and reload your synth to see if that makes a difference. I tried to experiment a bit but couldn’t reproduce this either.