I have the same problem with my 300SE. I have not found the problem yet but I suspect more and more the tires. I use bridgestone potenza on it.
I did have iot aligned and returned. The guy put it perfect in the specifications. But in the end we swapped tires from left to right and corrected the right pull. Although the problem of road crown was still there but less apparent.
Let me know what tire you use and see if we have a common thread here. Does this ring a bell to anybody?