I'm using a KL23H251-24-8B stepper which is 8 wire. it was wired bipolar series and it ran it for years with no issue when hooked up to the G540 driver.
I switched controller and driver to KL-6050 and encountered a weird knock in the motor after movement. It was somewhat random and you could hear the knock about a third of a second after the move. it sounded like the stepper locked into position each time. I also noticed that the movement was choppy in that you could see the axis sort of pulsate as it moved. So I purchased another stepper thinking something was wrong (these steppers get real hot) and the same thing happened. I switched drives around and even channels no help. Since I had the old stepper I could run the stepper by itself and confirm the knock came from the stepper.
So I rewired the stepper to parallel where both pairs of windings are in parallel ending up with 4 wires out and that solved it, the drive is now smooth. I'm not electrical but suspect it had something to do with high inductance when running in series. Apparently that inductance didn't bother the G540 but had an effect on the KL-6050.