Yes.Are they suppose to be like that?
I never really understood the UV light thing...I mean it’s not like the shoes were used in a murder....outside of the one committed on my wallet of course.
Helps with authentication.
It's not a widely known thing but this is one of the best ways to legit check certain pairs. TS1s, unions, and a few other "collab" pairs have these smudges on the midsole that is only visible with a black light. It used to be one of the best ways to authenticate fakes since they never had the smudges, I dont know if they do now though. (Granted they put extra on your pair lol)