The issue was that the database was using a case-insensitive and accent-insensitive column collation.  I've now migrated the street table to use a case-insensitive but accent-sensitive collation.  So, it will still group together streets that have different case sensitivity, but will properly tell the difference between streets with accent differences.  I've added Lidingö to the queue for a re-load, however, it's in line behind the other 13,000 cities that are currently being reloaded, so it's going to be several days before that gets corrected.  Thanks for the detailed troubleshoot!