Storyline slide stuck loading

I'm having an issue where reviewers (both in Review360 and in my LMS sandbox — we're using Cornerstone) are getting stuck on a specific slide with the three loading dots. Refreshing the page (in Review360) or closing and resuming the course resolves the issue. When looking in Review360, the screenshots that the system auto-collect show the next screen, implying that the transition is successful on the "back end" but this doesn't display to the learner. 

I've seen the posts about results slides — that isn't applicable here.

This slide is built from a template used 2 other times in the course — the issue is always on the last one, never the other two. 

It seems to only happen to each user once per platform, so testing is tricky. 

I'm using a hotspot as the trigger to change slides. The trigger is of the form "when the user clicks 'HS_Confirm1': Set (variable) to (other variable), Jump to slide (slide) if (other variable) =/= (blank)." See screenshot below. This trigger setup is identical to the slides that are working properly. 

The slide that is being loaded is also a copy of the slide that gets loaded in the other scenarios — the only difference is that the other 2 have video or audio that plays when the slide loads and this version does not.