text: Note that if you follow this road to the west, the continuation of it is, in fact, called Rådhusplassen. This name change happens conveniently right as you enter the open square in front of the town hall...
  
  My suspicion is that the data in OSM right now is correct. The part of the street next to the city hall is called Rådhusplassen, while the part that borders the coastline is called Jernteppet. This makes sense to me, at least.
  
  It could be that the OP knew that the first part was called Rådhusplassen, and just assumed the whole street had that name, as that would make sense if you assume a straight street shouldn't change name halfway though. But unfortunately this happens all the time.
  
  I suggest closing this note.