Publishing Online with Music: Audio files all play together instead of playing individually

I am using InDesign to create a presentation with MP3 tracks added on each page, published online. 

When I first published the presentation online, the tracks for the most part worked as I had hoped: One MP3 would play automatically when I went to the next page. (The only page that would not "Play on Page Load" was the very first page.)

Now, however, the same exact setting result in the the MP3 files bleeding together. When I press play on the first page, all of the MP3 files seem to play. 

My temporary solution was to uncheck the option to "Play on Page Load" which solved the problem of the music all playing at the same time, but now I have to press play on each page, instead of the next song automatically starting. 

The strange thing is that these setting worked pretty smoothly before: once I pressed play on the first page, each time I clicked the next page, the next song would play automatically. 

Has anyone found a solution for this issue? 

Thanks, 

M