Not 100% if it's a bug, honestly, but using Fire Arrow (and possibly other similarly animated skills) with the Kebob (lv 70 dagger) equipped, makes the weapon disappear during the attack animation. This happens even if you have a cash weapon equipped over it. Whatever you have just disappears during the animation.
It's a bug, but it's client-sided and a result of Nexon never implementing the arrow-shooting animation for the Kebob (because it's a dagger).
Ah, yeah, that's why I said I wasn't sure if it was a bug, being a dagger and all. Nothing to do about it then. Thanks for clarifying.