I think you just need to run the updateniceurls.php script in the updates/common/scripts folder. Look in the upgrade docs for syntax to run (can't remember which version it was in - probably 3.5)
or here - http://ez.no/community/forum/developer/update_common_scripts/re_update_common_scripts
When you delete an object and put it into the trash, it keeps its url (/residential).
Erase it from the cache and it should do the trick.
Alternatively, you could rename residential (with url __1) to temp save, and then change it again to residential. The url shouldn't have the __1 at the end.
Yeah, emptied the trash, cleared the cache, edited and saved the object, cleared the cache again, ran the update script again, cleared the cache again...nothing.
Had the same problem, Xavier's idea worked perfectly, just change the name of the node then clear cache, trash and drafts then rename it to the original.