Glitched Challenges not finishing?

[Kustomautos]

i finished one of my 4 challenges with friends then did 2 when playing with randoms but set myself up in all 3 of those getting over 80 kills with shotguns for my final challenge for 3 purple points. not sure what to do ive killed the last 10 zombies for the challenge 4x over and its not registering? is the challenge misslabeled where i need 90 kils in 1 match with shotguns or is it just bugged?

[droggen]

It could be bugged maybe the shotgun you're using does not count if you attach a mod on it who knows, I know mine to kill five zombies with a thrown weapon only worked if I used a blunt thrown weapon.

[Xraysteve]

I have the "Kill zombies with any shotgun" assignment and I know I've killed zombies with a weapon that's marked as a shotgun without any attachments and haven't gotten any credit with it.