As I've noted in various redistricting threads, this is actually quite common in states that allow extensive chops of election jurisdictions such as counties, cities, and towns. The GIS staff is typically more engaged with the transportation and tax assessment departments, and less often with elections. Even is there is tight coordination during redistricting, new houses and subdivisions will appear mid-decade, and geocoding for elections is rarely verified. I found two areas that were miscoded in a fast growing suburban IL county last decade, and I wasn't even looking for the problem.
