I had a similar problem happen to my HDM some time ago https://community.carbide3d.com/t/spindle-sandpapery-rubbing-sound/69651/11?u=thebigjam
It seemed to go away after warming up the spindle for a bit through the rpm range. I’ve done a lot of cuts since then and the sound doesn’t seem to be much of an issue.
I have noticed however that it makes this sound when the ambient temperature is colder <60-50 degrees, maybe that has something to do with it.
It hasn’t affected the quality of my cuts or failed, but I have noticed a slight decrease in torque when milling steel.
Here’s the gcode that I run for warming the spindle up: https://community.carbide3d.com/t/spindle-sandpapery-rubbing-sound/69651/21?u=thebigjam