The Meaning of Life, the Universe, and Everything.
I have not experienced any bug with maps in 1.13.2. When you generate a map in MC it is assigned a section of grid from the world to display based on where it was created and the terrain it displays can be 'zoomed out' to encompass a larger area but the terrain a map displays doesn't change if the player moves to a new area. You should a have cursor somewhere on the map that shows your actual position and the direction you're facing but if you can't see that it would be a resource pack issue, not a version issue. Did the map behave a certain way in 1.12 that has changed for you since starting 1.13?