I'm using the app on an android phone, and it's been generally picking up where I left off. I notice that every once in a while, it does screwy things. Sometimes you've got to clear things out and start fresh.
I recently noticed that the phone app always tries to start from whenever it was last stopped. So on the morning commute, it attempts to pick-up from the previous evening's commute, but there's a 5 or 6 hour limit. So at 6:30am, it starts me at around 1am. Couple this with the fact that the DJ chatter is prerecorded, and I get a strangely "off" sense of time.