Not sure whether or not this is a bug, but Din's Fire and Nayru's Love items that are removed when used do not work properly. A Nayru's Love item that disappears when used does not generate a shield or make Link invincible regardless of the duration. A Din's Fire item that disappears when used creates a ring of flames, but the flames merely stun enemies regardless of what the damage is set to. A Farore's Wind item that vanishes once used still works properly, though. Click here to see for yourself
Godess Spells that disappear when used malfunction
By "disappears", you mean if used as a one-time item, like if you were using a potion, correct?
Yes. That's what I mean.
Fixed!!!!!
There's still one little problem with a Nayru's Love that is removed from Link's Inventory when used. When the shield starts fading, it does not uses the Nayru's Love Shield 2 Sound effect (or whatever comes after what you set the shield sound effect to), and the shield sound that is assigned to the item does not stop playing.
EDIT: Now this one is 100% fixed!