i have a similar problem when connecting the op1 to other machines (asr10 and mv80000, via a motu timepiece midi patchbay) the op1 sometimes runs at double the bpm of the other machines.
i assumed it was a midi feedback issue – as i also get notes double triggering when using the mv800 and asr10 without the op1.
the motu timepiece midi hub i use is very sophisticated with filtering and routing etc. and should be able to defeat midi feedback very easily. i had some settings that were working, but i changed something and the problem returned. i can’t remember how i fixed it. so now i just yank out a mid out cable temporarily.
btw - the older motu timepeices sell for little. they make great usb patchbays.