Issue with Course Progress indicator

I'm having a bit of trouble getting a course indicator to work. Perhaps someone can help me with this!

I have a table of contents on the first page of my project, with a progress indicator for each section (each section is its own scene).

I have created a variable for each scene, which is designed to drive the status changes:

At the begging of each scene, the first slide has the following trigger:

So, starting each scene will set the status to 1 (if the status is less than one - I don't want learners who are re-watching completed sections to be set back to "incomplete".

 
The last slide in the scene, meanwhile, has a trigger to set the status to 2:

I have tried using both "when user clicks next button" and "when timeline ends" for this trigger.

These have corresponding triggers on the circle on the home screen (this is on a slide master, if it makes any difference):

My problem is that all of the circles will switch to status "Incomplete", but they will not become "complete".

Does anyone have any idea why this might be?

Thanks in advance,