Wrong texture of a bottle

I'm making a texture pack and was up to make the "potion_bottle_empty" texture.
I thought this is the texture of the "glass bottle" ingame..
But then I recorgnized that this texture isn't used o.O
The texture which was unsed is the "potion_bottle_drinkable" texture and I had another texture for it... so this is I think a bug??? o.O