Washroom door cracking

I think you need to give a bit more info than as the op, ie what make,and material etc

On my 2013 Elddis caravan we had a crack develop in the top corner of the shower cubical. It was repaired under warranty by our dealer who replaced the entire panel and did a great job. I asked why it had happened and he said they found a screw protruding through the wall structure framework  when the old panel was removed, this had been pushing on the inside of the panel since it was built but took five years to break through.  So basically a manufacturing fault. 

Hi its the actual wash room door on a Swift Sundance 2012, one side is a wood laminate the inside is while laminate, it appears to be cracking all around the inside as if the door had expanded?

It possibly has expanded. I think the doors are made of corrugated 'cardboard' and covered in thin laminate or vinyl. 

Washroom, steam, damp, 'cardboard' - hmm🤔