Fuzz after film rewind on NX

[kdemas]

I have noticed some green fuzz on the side of the film guides, like a tennis ball would give off, after rewinding film in the NX. The film used thus far is Portra 160VC and E100 GX Ektachrome.

Any ideas what this could be? I have never seen this with my other Contax, Nikon or Leica equipment.