This is a difficult one.
My character got into a buggy state were I was unable to remove my AKM from my hands.
Nothing else was occupying the inventory space on my back (weapon and melee weapon were gone).
Pressing the X button did nothing.
The AKM and Pickaxe were gone from my Quick selection bar.
Additionally I was unable to put any new item on my back. They simple disappeared when I tried.
Drinking a soda worked fine but placed the AKM on the ground.
I was unable to drag the weapon on my character but was able to put it back into my hands and use it normally. But it still remained bugged.
I decided to log out and back into the server which fixed the bug but now I had one AKM in my hands and an additional one on my back (Inventory).
First I thought it was an UI bug but I was able to place both weapons on the ground and interact normally with them as if they were to independent entities.
The Pickaxe that disappeared was back as well. {F31990}