Sorry for the misunderstanding. The "Weststadt" you are referring to is part of the city of Neu-Ulm and should not overlap the Ulm territory. I made a modification and it it should be ok now. 

BTW, you can verify at https://www.gisserver.de/neuulm/gtiweb/Geoportal/ . Just select "Kleinräumige Gliederung" and hover over the neighborhood. Note that the Geoportal is just for verification and not to be used as a source for OSM. The  Geoportal content is not compatible with the OSM license conditions.