Meanwhile, to my surprise I found a comment by @OttoStover that he wrote more than 10 years ago in our German outdoor forum and that basically answers my question. He hiked across the mountain pass between Sørfjorden and Paurohytta and he confirmed that in reality, the route runs far away from the trail drawing on the map. If you look at the screenshots from my navigational app at the beginning of this discussion, the ascent to Baurifjellet, according to Otto, would be closer to height 851 and 862, which is about 1 km north of the trail drawing and of my own route. The map shows a small emergency shelter between 851 and 862, and Otto's route at that time touched this shelter (I don't know if the shelter still exists).
So the trail drawing on the map, unfortunately, seems to lead people away from a safe route and into rather risky terrain instead.