Hi, Andrew.
Thank you for reaching out and sharing your .story file!
When I previewed the .story file, I didn't notice any freezing happening in the first three slides. I also uploaded it to SCORM Cloud, published as an LMS package, and it worked as expected. You can see my test here.
When you tested the .story file, did you have it saved locally on your hard drive? Working on a network drive or an external USB drive can cause erratic behavior due to latency.
If you are still experiencing the same issue with your file, the next step would be to connect with one of our support engineers through a case.
