I have the same problem on one of my calipers too, i have read somewhere that the calipers are powder coated, on my caliper theres a patch about 1 diameter peeled off, haven't found a solution to it, or even if there is one.
The paint on Brembo calipers is powder coat,u cannot sucessfully touch this up.
Even if u cud anodise the calipers ,which u can't because they are castings, a winters use wud destroy it.
Peeling powder coat is probably caused by a combination of faulty original application ie the calipers were not fully degreased before coating , the operating environment , hot/cold , hot/cold , winter salt , wheel cleaning solutions , pressure washing , stone chips , heavy handed wheel fitters etc etc.
The only solution outside a warranty claim is complete strip and re-powder coat.
1/ this will be costly due to the work involved on those big , complex calipers.
2/ Where do u find new Brembo decals ?
This is where my philosophy on using my car has it's advantages , as in I may be mad but by not using my car in the wet or winter, everything is still virtually as new as the day I took delivery , both underside and topside
I am going to my dealer tomorrow as suddenly all four of my calipers have started to peel. Will let you know the outcome. CCC agreed to refurb my alloys FOC under warranty, let's see how they react to this problem.