Strange, seems like the primer paints/sealants not painted/overcoat with normal top-coat grey paints..
Bro, is ur car new/or 2nd hand 1? Normally when we check for "accident-free" 2ndhand cars, this is 1 of the area we will check, to make sure all the joints/connection area is as original, no additional touch-up done..
If urs is new, since day 1 u notice this? Or is it TC does a touch-up without ur knowledge on 1 of ur service?