A stepper motor usually does not struggle for life. If it has to move against a force that is too high, it looses steps. The controller has the ability to recognize that.
Also Onefinity stated here that a heavy spindle using 80 mm mount would be no problem. The 80 mm mount has not been released without longer testing.
I would suspect that there is some backlash/clearance somewhere.
What spindle do you use?