Slides are skipping in Captivate 9 published output

Hello,

I recently completed a software simulation video in Captivate 9. (It's a non-responsive project). Everything plays beautifully when I preview it; however, when I publish the file as an HTML5 and SWF file and view the published output (viewing the multiscreen file), the file will randomly skip over a slide or two in the middle of the video. Both the video and the audio skip. If I hit the "replay" button or the "back" button, the skipped slides play perfectly.  I tried publishing the file just as a HTML 5, and when I viewed the published output it played perfectly, with no skipping.  A few questions:

1) Does anyone have any idea what could be causing the skipping?

2) Our group has been in the habit of publishing everything as a SWF and HTML 5 and then giving that file to our web team to put online. (We do not currently have an LMS).  Is there any reason why we shouldn't just publish as an HTML 5 file & post that version online, since that one works perfectly?

Thanks!