@Con-Hennekens @Jörgen :
I absolutely agree with you about the different meaning of via and shaping points. I also like the algorithm according to which shaping points are automatically skipped.
In this specific case, of course, I didn't want to skip route points 12 and 13, and the interesting question is how to prevent this.
I looked at a few routes from the MRA library to get an understanding of whether there is a kind of "standard" for dealing with route points that relate to POIs / favourites or should otherwise be given a special meaning. It seems that such route points (in addition to being coloured other than blue) are then set as via points if the author recommends a "mandatory" stop here. However, if it is more of an "opportunity", a shaping point is set. From my point of view, this approach is correct and good and I have adopted it in the same way when creating my own routes.
That is why I would not set one of the points 12/13 as a viapoint (because they are "opportunities"), but instead add another (blue) shaping point and/or move point 14 a little. What do you think about this?

In any case, it is good to know that with such loops in a route, a "shortcut" can arise in the event of an auto skip, which one may not want at all.