neutral density

Hello everyone: I am thinking about buying the V7 filter holder from NiSi. I would like to know whether all 100×100 mm ND filters from the brand include the foam gasket on the back to prevent unwanted light from entering through the sides, or whether I should consider buying replacement foam...

I just recently purchased a Formatt Hitech 95mm Firecrest solid ND filter (2.7/9-stop) for my D810 and have been coming up with a pink line in my photos (happens regardless of shooting into the sun/light or not). Any ideas as to what my problem is? I'm using it with my 15mm Irix full frame...