I’ve recently encountered the bug where DLC items and shillings will disappear if DLC ownership is not recognized by the game. This is explained in this Fatshark Support article: https://support.fatshark.se/hc/en-us/articles/360005177317--PC-Help-Why-Have-My-Items-Disappeared-
In my case, while the missing DLC items and shillings got restored after restarting the game, the favorited DLC items - both weapons and cosmetics, lost their favorite status in the inventory after the restart. This was frustrating since I’ve favorited a lot of DLC items, and I’ve got to go to each character’s inventory to re-favorite and try to remember which ones I’ve previously set.