It appears the problem is due to the rapidity of calls to get the refresh token. I have a loop of calls to refresh the token 25 times. When called I get several successful refreshes, then, I get just an access_token and token_type. But, if I add a 5 second delay between calls, all 25 work fine. Given that 25 immediate consecutive calls isn't really a valid use case, this doesn't appear to be a problem. I originally was just experimenting with the API call to get a refresh token when this problem occurred.
... View more