Yep, and you can expect your shower surround to crack because of the same reason. Manufacturers just drill screws right through the plastic surrounds, giving no wiggle room for expansion due to heat and cold extreme temperatures. With no way to expand or contract, the screw holes are always the first place to give, causing all kinds of cracks in the surround. (solution is simple, before screwing the screw in, the surround should be pre-drilled with holes slightly bigger than the actual screws being used. This allows for some wiggle room.
(my current trailer has plastic push button molley bolts holding the surround in place. The holes are drilled out bigger than the actual plastic bolt too. This one hasn't cracked yet. So sad it happened to my previous camper though.
Yes, expansion and contraction of the building materials in any camper without wiggle room is a crack just waiting to happen anywhere in the unit.