My cracks are at the top of the slide hole.Here are a couple pictures of my same exact issue with our 4007 bedroom slide.
The interior photo is looking behind the main bedroom slide on the forward side. You can see the top Schwintek mounting screw misses the aluminum frame in the wall entirely. The gap between the "column" and the wall frame goes from tight to 5/8" - 11/16" gap at the top.
My livingroom slide hole is also out of square. The right vertical drag seal has a 5/16" gap between edge of seal & slide.
I have a total of three existing high wall cracks and one large "bulge" that has yet to crack.