I can't see the enemy's HP bar. Help?

I don't know why... I just realized it, sadly. I'm fighting a certain boss in Kingdom Hearts (Cerberus) and the HP bar isn't showing for it. It's showing mine, Donald's, and Goofy's, just not Cerberus's. So I have no idea how close to killing it I am. If I remember correctly, I didn't have this problem with the last boss. Can anyone help?