You may have gotten a defective booster. My chocolate cards are great; however, my Twilight White expansion is definitely thinner and not cut exactly the same way. It's frustrating, but I haven't purchased a new deck yet.
they are all thinner now. when they were all reproduced they changed the card stock. i know this because i asked at gencon on why they changed the card stock. they also updated some of the cards to match the way conquest backers look like. but for some reason they did not due this with the reprint of the blue starter kit!!!! for quest. only after blue and yellow. so red has the new backers.