It looks like this may be due to errors during audio.play(). There are errors in the console when this happens:

Uncaught (in promise) DOMException: The fetching process for the media resource was aborted by the user agent at the user's request.

If so, we would need to handle the promise returned by play() and maybe try again if it fails.

This happens when Player.skipAhead() is called on the "ended" event, but not when skipping ahead manually, which also uses Player.skipAhead(). My guess is that there are somehow two callbacks to Player.skipAhead(), probably due to failing to load the first time, which causes it to skip ahead twice.