Not sure. It sounds like even with MIDI thru off the note information is being sent twice. Are you programming the SR16 and sending the patterns to logic? That could be it. If you are triggering it from the pads on the SR16 that could be the problem too, it is sending itself the notes and also sending logic the notes, logic is then sending the note information to the unit again. Since there is no option to turn off local control, try triggering/sequencing the SR16 from a different MIDI controller, or using the piano roll in logic and see if that helps.