Jeff.. have you ever heard of this issue before? it seems really odd that the shifter would move like this for a brake issue, but the foreman seemed to think it was normal.Have you spoken with your dealership about this issue yet? They would best be able to give you a diagnosis for you to start from to fix the vehicle or have the vehicle fixed by them as well. I hope this helps and if you run into more problems feel free to contact me.
Jeff Morris, Cadillac Customer Service