Didn't try to reproduce it but this is what happened.
I had an AKM in my hands when a player decided to attack me with a Fireaxe. I shot him and noticed that the melee swinging sound was still playing in repeat.
No animation and nothing was hitting me though.
I picked up the buggy Fireaxe by replaying my Pickaxe with it while I still had the AKM in my hands. Here is were the buggy behaviour started. I ran away and noticed the swinging sound was following my around. I decided to pull out the Fireaxe which didnt work but it placed the AKM on the ground. I then decided to go back to the dead player from earlier to get my Pickaxe back. Dragging it back on my character removed both the Fireaxe and the Pickaxe.
Picking up a new melee weapons didnt work. It got removed as well.
The AKM was stuck on my hands but I was able to use it normally as described above.