unable to play Audible/Tune-In Radio from locked screen.

I have noticed that since I updated to IOS 7.04 (I have an iPhone 5), my Audible books and Tune-In radio music goes off when the screen locks. There is a control on the locked screen for play, but when I press it, nothing happens. This used to work without disabling the auto-lock setting in the application. The native music application seems to work fine from the lock screen. Is this a bug with IOS 7.04? I noticed the battery usage was much poorer for Audible if I disable the auto-lock in the Audible settings. Any information much appreciated Susan N.