i) the tiles bent upwards at the corners while playing. Don't know if the humidity in the room was too high, but I don't think even with it should not happen so fast. Is there some way to bring them back in shape for a plain game board?))
Any difference in humidity from where the product was packed and where it's opened will result in curled corners (much more likely with cheap material too).
90% of my games curl after opening. Just get them under something heavy for a few days and hope.