Creaky noises on iPhone 15 Pro Clear Case

I bought from authorized store an iPhone 15 Pro clear case for 59€. When I came home to put it I realized that it is a bit loose on the sides and moves when I press there and making these creaky noises. This didn’t happened with my old iPhone 12 clear case. When I came to the store to ask about this, they said that it should be like this, so the bottom corners wont crack, but when I went to forums some people said that I shouldn’t be like that, and I don’t know who is correct about this.