@dc42 Yes, that is what I thought as well.
Do you have any idea why timing is so far off? Like I mentioned above, I successfully tested these motors with the same power supplies and a MKS SGEN controller board with timings of 3:3:6:6. The MKS SGEN board provided 3.3V logic, so if anything I would have assumed it would need more time to activate the opto-isolators due to the underpowered signal.
One concern I have is these motors are supposed to run at a maximum pulse frequency of 250 kHz. Is there a way for me to set that for the Duet board?