I recently upgraded my hotend to a hardened steel nozzle and noticed black flakes on the guide rods near the idler pulleys for the 4th time after having cleaned them off before. I noticed the belts on the pulleys closest to the tool head sit either at the very top or very bottom of the idler pulleys.
I have P1S. Its less than 2 months old
I did try adjusting the pulleys in the rear again. I accidentally loosened them when I first got the printer and adjusted them tight. I later loosened them a bit but made sure the belt ran center while moving the toolhead in various different motions.
Print quality is not affected, yet. There are no odd noises from printing. There was an odd, very low tone, “BRR” sound when printing long circular shapes. I was told its normal since it only happens during very specific shapes.