Sub37 & Ableton

Dear all,

I’ve created a simple arp style 4 bar loop that is being sent out to my sub37.

I hear audio, midi is being sent . But the proble is every 2nd note is skipped . So instead of C E G B C hear C G C . Tempo is set at 84.
Am using the usb midi and disabled DIN and midi out just in case but to no avail.

Any idea ?
Tx

That might be related to the polychain settings

I configured the default settings as indicated in the manual but no change. Any other advice ?