I walk on a treadmill for at least an hour. I set the workout to indoor walk. Yet the activity ring (which is set for 30 minute goals), never closes. It will close for an outdoor walk.

Not always, no. But I read that if my arms are swing freely, it calibrates better. I'm usually reading a book while on the treadmill, so my hands are occupied either holding the book or turning pages. I'll bet that's the issue.

Answering the other response: Yes, for other workouts it does record as expected.