Not quite sure what’s happening here. For context, I’ve set “Use percussion map” in Note Input and Editing options, and I’m inputting Kick drums with C2 (middle C being C4 in this case), side stick with C#2 and hi-hat with F#2. Each of these goes in fine by themselves but when I play all three notes together I get a random extra kick drum.
I don’t have this issue in “Staff position” mode but in this particular case my kit has hi-hat and tom 1 sharing a staff position, so unfortunately I don’t get consistent results when playing E5, sometimes I get hi-hat, sometimes I get tom 1.