I'm thinking this is my issue. I temporarily takes taped over my Third Brake light to rule that out. I think it must be my roof seam. Do you have that TSB info? I would like to see if I could get mine figured out.My 2015 is at the dealer right now having this take care of. Water leaking from drivers side pillar grab handle. Originally focused on 3rd break light and front window seal. They ended up finding a TSB on the roof seam strip tested that and found that to be the issue. water would get into that channel and work its way down and out the grab handle screw hole. Parts had been on back order for about 4 weeks, they are in now. Dealer is removing, resealing and installing new roof strips. They had to keep it overnight for the sealant "to cure", crappy jeep compass loaner for me. But hopefully leak free this winter.