Drupal 7.41, Civi 4.6.9
The scheduled reminders are working except for 1 or 2 per day might not be sent. It appears random which ones don't get the reminder sent. The 1 or 2 a day is based on a rather small sample size. This client doesn't have all that many memberships so it's usually 5 or less reminders for any given day. Sometimes none are sent.
I have looked at the members/memberships that don't get reminders and I have not been able to find a reason those members didn't get a reminder while others have on that same day. If anyone has experience with this I would sure appreciate any help you might have.