devtrackers.gg
Happened after everyone's Expertise Table got recalculated (so a while ago). My XP for using weapons and equipment (and for donating) still tracks, but any expertise levels are lost when I log out/log back in. The Proficient list still tracks (I'm Proficient with 101 brands/weapons), but it might as well be '0' too, since I can't upgrade anything.
I was really excited to have something to grind for again, but even if its fixed, I can never upgrade my stuff as high as other players, right? Because I'll always have 100 less proficiency ranks. I sincerely hope the irony isn't lost on you.
Oh, and on one of my Hardcore Agents (whose on the NYC map), any time I open the Tactical map and attempt to go to DC, when I hold X while over the DC map icon, the game freezes, and crashs back to X-Box home screen.