Off hand, I'd most strongly suspect form problems as being the primary causes of misalignment. Be it a strongback that warps, to asymetrically cut forms, to failure to ensure perfect alignment of the forms.

As for the stresses causing failure, it actually enhances strength. As an example, take a sheet of thin plywood, and you can notice how floppy it is, and how weak it is. Stand on it and you will go right through it. Now bow that sheet. It immediately becomes rigid, and you can now stand on it. You gain part of the strength by the shape change itself, and part ofthe strength by the stresses.