That's normal. It's a slight graphical error, but no there's no in-game problems caused by it.
When a creature with an active ability with an activation cost gets hit with Liquid Shadow, the game doesn't quite understand what to do when its new active ability doesn't have an activation cost. Hence, the strange 1 quanta of its own element 'cost' to Vampire. Note that Vampire is a non-activated active ability, so it can't be activated before attacks occur. That prevents any potential weirdness that could happen.
