Custom replay/restart slide button

I have created a course with several slides that have multiple screencasts and audio voiceovers in the timeline.  They are set on the timeline to run at specific times so that they all match and follow on from each other.

I have created a custom "replay/restart slide" button with a trigger to "go to slide - this slide" when clicked.  The slide is set to "resume initial state when revisited". 

In Preview the custom button works fine for the audio - when clicked anywhere in the slide timeline the timeline restarts and audio plays correctly.  However, the screencasts do not work properly.  If the replay is clicked during the first screencast it works ok and restarts from the start.  But if it is clicked during the second screencast the timeline restarts, the audio plays, but the first screencast does not play - the second screencast plays at the correct point in the timeline.

Can anyone help please - I really would like end users to be able to replay the current slide.