Good Afternoon. On the MK10C when I removed the rear rotors to rebuild the calipers and turn the rotors to remove surface rust and truing, I found these weird marks on the splines of the stub axle. They appear to be man made but why? To help hold the hub on the axle by friction? Both sides are the same but on the MK 8(10) these marks are not present, supporting man made.

I have heard of breakage of the IMP stub axles on other formula cars and wonder if these “filings” are weakening the stub axle? For now, I plan to use as is but maybe should start looking for replacements?