new hunters pickaxe is invisible on the ground

It's visible on the ground for me.
Must be your client. You might have a client mod installed that replaces items with "HD" graphics.
I used one of those for a while and when the nordic skin set was released suddenly Wigfrid's battle spears were invisible on the ground for me but not for other people I played with.
Disable this mod in your mod menu and try again.

Edited May 28, 2020 by KainMorgen

Changed Status to Closed