Today, I was removing a villager spawner because SpplatPT said I could. I was using my diamond pickaxe. Then, I went to one of my bases to mine some iron because I didn’t want to waste my diamond pick. When I was in the cave, I stopped to look in my inventory to see if I had any iron. When, all of a sudden, my diamond pickaxe disappears. I hope staff can look into this, because I don’t want this to happen to anyone else. Your friendly Trusted, Potato321.
Did you get your materials back? It may have just un-crafted itself.
No nothing I don’t even have the pick anymore. 
Ah. I had this happen to me once, but it was a small stack of signs that vanished into the beyond.
Hope it gets replaced.