Mq Help.

[Kele]

I'm playing through Master quest and i just played through Water temple.
I found all treasures and skulltulas and rooms and i still have one extra
key.
Is there something wrong in my game
or is this normal?

 

[Welbanks]

Well, since you've beaten it and have all the treasure chests and skutullas, it dosent really matter does it?
I suppose just move on.