WotLK Heavan's Fall Dagger Bugged?

[Cotes20]

When in inventory the icon is a question mark cannot enchant it or apply a weapon poison to it also cannot use any of my abilities that require daggers or melee weapons. Is this weapon bugged or am I missing something here my other dagger is fine.

https://wotlk-twinhead.twinstar.cz/?item=50736
Dagger for Reference