When opening the gui of the list item every enchanted item in the upper row of the player inventory has a render bug exactly then when you don't mouse-over any of the buildcraft slots or the upper row of the player inv (while all other slots are rendered fine in either case) (in the pictures it's the pickaxe)

(Mouse not over one of the two rows of slots)

(Mouse over the 4th slot of the 2nd row)

try reproducing without optifine, if optifine is the cause we can't realy fix it due to the heavy rendering changes it does

happens without optifine aswell (exact same behaviour)

7.2.5 and optifine