Does my toilet have a manufacturing defect?
I know this is an old thread but in case more people come across it I have added this post.
I have a brand new Kohler Ciimarron elongated bowl toilet that I installed and had the same issue with wobble. I pulled the toilet and used a straight edge just as you did in the photo. It has the same issue of the small support ribs are taller than the outside rim by  strong 1/8”. The casting is defective. Yes they are made in a mold but there is the opportunity for defects even then . poor quality control on Kohler’s end. I am returning it right now. I will try a different brand. My guess is that they are all manufactured overseas which adds to the issue.