I've given up using these potions because whenever I do, for some reason I get the message that I'm becoming visible again almost as soon as I've drank the potion. I know you have to keep the mana up since it uses mana to keep you invisible. Does changing levels in a dungeon force you to become visible and is it just plain impossible to use in certain situations. i.e., where the game wants you to be visible no matter what you think?
Drink Up Ye Cider. 
