If anything, quite the opposite. Padme bore twins which were seperated at birth. The answer is simple, we were never told the Liea had Jedi powers. The original prophecies told of A Skywalker that would balance the force. It just never said which Skywalker. The only real evidence we had is that Luke and Liea both 'sensed' each other, but we never saw her really perform Jedi tricks or abilities. I may be forgetting something, but Im pretty sure.