I'm not sure that the data's to blame. For comparison, I've just given CoPilot Live a try with a couple of other streets (Korotyńskiego and Dickensa to be precise), and the UI presented them to without any difficulties.

These aren't new streets, they're on every map out there, and I'm convinced that this is a programming issue of not handling the data correctly. It's not even a case of doing cleverness with letters such as ń or ó - it's a complete failure altogether.