For the people who are talking about computer RNG: If you have six actual cards to draw, and you shuffle one back into the deck, there's really no practice currently in card games/fortune telling that would give you the same card again. You don't shuffle the whole deck for one card. Unless the astrologian has a deck full of the same six cards copied four times or something, which strikes me as staggeringly dumb. There's no way for this to happen and your character not to seem like a total idiot. Which is reason enough for me to say this is definitely an oversight, to say nothing of the frustration one must feel in using an ability which has an aspect that makes no sense.