Next button issue in Chrome

Hi

We have a course that has a slide with triggers that require the user to complete 6 interactions before they can move on.  Each of the triggers sends them to a different slide before returning them back to this main slide.  The triggers are set so that the Next button is hidden upon arrival, and only appears once they have completed the 6 actions (I have added screenshots showing the triggers that have been setup).

This all works well in the preview mode, and in Internet Explorer, but in Chrome, the Next button doesn't appear!  And as the majority of our organisation uses Chrome, this is a definite problem for us.

Does anyone have any idea why this might be?  I didn't create the course, but I can't see anything in the triggers that would cause this, however, I am relatively new to Storyline, so fully accept that I could be overlooking something obvious.

Thanks in advance 

Mark