Please note that your app status will say “Estimated time to Approve” as a result of setting Future Release Date feature. When you set a specific date to release your app or app update to the Amazon App Store, your app status will be in approved status until the specific release date. Once it reaches the specific release date, your app will move to live status.
For detail on Future Release Date feature, please go to What is a Future Release Date? How do I add one?