I was jogging with a pickaxe in my hands, pressed "V" to vault a fence and the pickaxe disappeared from my inventory and the hot key. Thought oh well its alpha and carried on. Later I found a baseball bat and dragged it from the vicinity part of the inventory to my character but it did not appear in my inventory even after several tries. but could drag it into my hands. Then found I could not drop the baseball bat but managed to throw it with the "G" key. tried to equip again but without success so dragged it into my hands and logged off.

Logged back on a few minutes later and my pickaxe had reappeared on my shoulder and the baseball bat was in my hands. Dropped the bat ok, added the pickaxe back to its hot key and it worked as it should.