I somehow have two axes, not sure what happened and I only noticed it when I was looking through my chests. It might've been a glitch when I used the 'find missing tools' thing at the blacksmiths.
#Duplicate Axe
lavish flare
naive pivot
I've been having similar problems as well! My pickaxe has been duplicated when I collected it from upgrading it as well as my flaming sword has duplicated twice. I don't know how to replicate it unfortunately.
I'm on PC and it started happening just before the v1.1 1225 hotfix.
My current version is the v1.1 1226