Cartographers table shows wrong zoom level for target

When adding another zoom level to a map by combining a map and a piece of paper in the cartographer's table, the resulting map in the output slot shows the same zoom level as the input map in the mouse-over "Scaling at... " text as well as the "Level ... /4".

Once the user takes the map out, the zoom level is correct is correct. Only the mouse-over of the target map while the map is not actually created is wrong.