Slides appearing as blank white

I am having an issue where some of my slides are randomly appearing blank like in the picture below:

This course was built in Storyline 2 with an imported powerpoint that has audio playing for each slide. It has been published as SCORM 1.2 and was forced to run the HTML5 version by editing the index_lms.html file to always load index_lms_html5.html (something I do with all of my courses, and this issue isn't one that I have encountered with any others). It doesn't happen consistently, which means that it has been very difficult to isolate the issue. I am unable to post the actual course here for people to take a look at, and the inability to isolate the problem means I can't recreate it in a dummy project to attach here.