Efficiency on Gold Pickaxe Mines Diamond Ore Slowly

Expected:
Enchanted fresh gold pickaxe in 1.4.4 with efficiency IV, unbreaking III, fortune III. Updated to 1.4.5, found diamond, going to mine it and receive lots of diamonds.

Actual:
Pickaxe breaks diamond block very slowly, as if it is an incompatible tool and will not drop a diamond. I don't want to risk losing the diamond, so I'm not sure if it'll drop it or not.

Steps to Reproduce:
Enchant gold pickaxe at level 30 in 1.4.4, update to 1.4.5, use pickaxe to try to mine a diamond ore.