Only on one area (The underside) as the rest of the model seems to remain the same.. So it may be, as IRobertI said, something with the model may be off. And, the closeup views were much more helpful.
Can you upload the file so someone can take a look at it? I, personally, like to solve problems and add to my brain attic of things that can go wrong.
Ok.
STL file.
Please test it.