Headset cup and steerer tube wear on rear side
I have a Cervelo Prodigy with an Aheadset threadless headset (unsure of model--it's the one that came stock on the white and silver Prodigy).
When I went to overhaul the headset, I noticed that there were worn spots/rub marks on the "back" of the steerer tube and top and bottom headset cups (if 12" oclock is pointing forward, then the marks are from about 5-7 o clock).
They're deep enough to be perceptible by running my fingers down them with my eyes closed, but probably not deeper than a piece of paper.
What would have caused this? Worn bearings/races? Misadjusted headset?