text: Yes, we know that. :-)
  Historically, metro lines were drawn in a very primitive way on the map: one single line and one node across it for every station.
  In the last years, I have patiently been surveying every station to make accurate drawings: this involve two tracks, but also correct platform geometry, stairs, escalators, and so on.
  Line 6 is almost complete but I still need to survey Bockstael, Stuyvenbergh and Roi Baudouin/Koning Boudewijn.  This is planned in the next weeks.  That explains why this part of the line is still shown as single tracks with very basic station structures.