I don't think calcium chloride would be an issue. A potential variable that you didn't mention would be room temperature. This could affect whey drainage. As Brie pointed out, too much whey left in the cheese after removing the mold may cause it to lose it's shape. If your room temp was cooler than normal, you may not have had as much drain as normal. A side note, we don't use molds for a "tube" shape. We bag drain, then we allow the cheese to rest in the fridge over night. After that we can weigh the perfect amount for each piece of cheese, form it into a ball, and roll it into shape by hand on a cutting board. Have you continued to have any issues? Oh, and was it the whole batch of cheese that ended up shaped oddly, or just a few?