How is the die for Cat Tower configured?
A comment from the publisher on their Kickstarter page answers your question perfectly:



This is their answer, but I'm also seeing complaints about unevenly shaped dice. If this is the case for your game, you should try to get your dice replaced.

If you can't get your dice replaced, make sure you don't put duplicates on opposing faces. You want dissimilar vales to oppose each other (eg 2 and 5 on a 1d6) to negate the effect of having a flattened dice.