Screen reader disregards player button states

Hi all,

I'm using Storyline 3, and I have the Next button disabled until the timeline ends. The course is failing accessibility testing because, as the tester says, "If I tab to the Next button and keep it highlighted, I am able to skip videos and pages that do not have an action that must be completed." (On screens with activities, if the learner clicks Next before all activities on the screen are completed, I have a layer that pops up and tells the learner they must complete the activity before advancing. Obviously there's nothing like this on screens with just text boxes, a video that plays automatically, etc.)

To further clarify, a tester using JAWS is able to tab to the next screen even when the Next button is disabled (s/he doesn't have to wait until the timeline ends, as I have it set up.)

Is there any way to make a screen reader recognize the difference between the Normal and Disabled states in player buttons? Thanks!