The loss of streetnames in the anouncements and the slightly different directions suggest to me that - at least at the time you generated the route - the client did not have a stable networkconnection. Does this ever happen if you start while still in reach of wifi (as opposed to relying on your 3G r GPRS-connection via AT&T)?
http://img.tapatalk.com/d/12/11/29/3ysemave.jpg
(Mind the little triangle and the red line in the middle)
http://img.tapatalk.com/d/12/11/29/3ysemave.jpg
(Mind the little triangle and the red line in the middle)
iOS 3.5.1 official feedback thread