pxlxr
3
First, read up on what midi notes/cc’s do within the sequencer.
Are you using OP1 as a controller? If so, you may be inadvertently sending an “Active track down A (69)” message.
I’m not too familiar with the OP1. Does it have polyphony settings?
Are you using the autochannel?
Have you loaded up the software for the ICM4+? It is pretty powerful and fairly well laid out for comprehension.