Originally Posted by
avrilboazmoss
i just wanted to know if it is not something like “usual” aluminium extrusion process defects
No, the blemish is on the machined brake track, which is a process after the extrusion. It looks like shipping or storage damage to me, perhaps jostling against something hard enough to leave those marks.
In any case, I would consider it a cosmetic, not a structural issue. It's your call if you want to return it.