How to progress objective nine of Expert Gunsmith missions?
Solution 1:
As of December 4th 2019, the tracker began working. I literally did nothing different to get it to work. This apparently was indeed a bug with this specific mission. I believe a patch from 11/22/2019 addressed this issue:
Progression/Challenges/Missions Fixes:
Cleaned up and updated descriptions for various challenges
Officer Challenge: “Heads Up”
“Destroy Vehicles with Launchers”
“Doing Work”
“Aggression”
“Expert Gunsmith”
“One Trick Pony”