I had this problem also. The answer was that my controller was sending MIDI on two ports (i.e. USB MIDI In A and USB MIDI In B). When I selected “All MIDI Inputs” for the input source for the track, it was receiving two sets of notes. You could tell your track to only accept the input from a specific port rather than “all MIDI inputs” or tell your controller to only send the MIDI data on one port. For my controller I had the choice of “USB MIDI In A” or “USB MIDI In B”.
Sincerely,
J.L.
You could also go to Devices → Device Setup, select the MIDI Port Setup. Here you can tell Cubase which MIDI Port inputs to include in “All MIDI Inputs”.
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