Name: Steel Heavy Miner's Pick
Where:
The bug is found on the item itself, attached to the haft of the axe.
When:
Upon the creation of a crafted Steel Heavy Miner's Pick
What:
There's just a bag on the handle of the axe. You can fix by changing color of the base and then cycling, but it can be a little counter intuitive.
Recreate:
Create a Steel Heavy Miner's Pick with 4 Steel and 1 Wooden Shaft
Ideas:
Probably just a weird texture, not sure if it's something that can be removed/edited.