Timeline end trigger not firing in IE8

Hello, 

One of our client's client's wanted the ability to entirely lock down a course requiring them to see and hear all of the content on every page prior for them to move on. One of our developers created a fairly simple system, with triggers, to allow this to happen (since it's not a standard feature within storyline).

In the Slide Master the main base template has a trigger which sets "curSlideComplete" to false "When timeline starts". Every slide's 'Next button' trigger has a condition on it which checks if "curSlideComplete" is true prior to advancing. Additionally Each slide, depending on what type it is (animation, interaction, video etc.), has a different system for how it  sets "curSlideComplete" to true. 

The most simple of these systems is the animation type which simply sets "curSlideComplete" to true "When timeline ends". This seems to work in every browser that I have tried it in except for IE. I am using Windows 7 with with Service Pack 1 and IE8.

As you can see in the image below the "curSlideComplete" is not changing at the end of the timeline therefor not allowing the user to advance. I'm hoping someone can help me come up with a solution to this issue as our target platform for this client is IE8. Thank you in advance!

here is the link to the course on SCORM Cloud

https://cloud.scorm.com/sc/InvitationConfirmEmail?publicInvitationId=828c1835-c3c4-4c1e-9dcb-7977ac72b442