Season 2 Catch-Up Challenge Not Tracking Properly

I've received multiple "destroy vehicle assists" in game when hitting aircraft with the IGLA but the only time it ever counts towards this challenge is if I fully destroy the vehicle myself (or get the last shot on it)

Kind of a pain in the butt since I got 3 of those in the last round, enough to complete this challenge, but they didn't count.

Also, the fact that I already own this unlock for completing the challenge and the challenge even exists in the first place is kind of silly - but that's a topic for a different conversation.

I completed all of Season 2 challenges and got all unlocks, yet these things still show up as being 'unlockable.'

Make it make sense.