It's simple actually.. It induces an artificial rudder input, which in turn makes right rudder inefficient.
Three years ago it wasn't like this. I posted a YouTube video (in Dora section) that I've made in 2017. It shows rudder in neutral on the ground before taking off. So this unusual behavior was introduced later with no explanations and quite inaccurate. The Bf has also trim tabs and it's NOT affected in this way.