Hello all,
I have the same issue.
Whatever string for the city of Leipzig and the surrounding rural district around Leipzig I use, it always shows them as a combination of the two in the area map, as if there was only one county for both of them combined. This is, as David already stated, incorrect.
To be clear, the following strings for the different counties I used always result in the same area in an area map visual, and the resulting area is always just the two different counties together:
'kreisfreie Stadt Leipzig',
'Leipzig',
'Stadt Leipzig',
'Landkreis Leipzig'
Again, as you can see e.g. in the table presented on https://de.wikipedia.org/wiki/Liste_der_Landkreise_und_kreisfreien_St%C3%A4dte_in_Sachsen, the city of Leipzig and the surrounding area are two different counties.
If you need further information on this, please let me know.