When you click the Rewind button at the far right end of the seekbar, triggers that you've configured to execute when the timeline starts will fire again.
This is the expected behavior, but it may not always be desirable. If this behavior is problematic for a particular slide, disable the Seekbar and Rewind button.
For an Individual Slide
To remove the Seekbar and Rewind button from a single slide, uncheck the Seekbar box in the slide properties.
For the Entire Course
To remove the Seekbar and Rewind button from the entire course, uncheck the Seekbar box in Player > Features.