Several years ago at the Cinematheque Francaise, someone asked me for details on the famous butter scene.
That is where the misunderstanding lies.
Maria knew everything because she had read the script, where it was all described.

Credit: Everett Collection
The only novelty was the idea of the butter.
Bertoluccis statement acknowledged Schneiders distaste with the way the scene was captured, however.
I learned many years later, [I] offended Maria.
Not the violence that she is subjected to in the scene, which was written in the screenplay.