Default Variation chosen but not all selections are made on front end

[jerryattric]

I have installed and selected the default for a couple of products manually to run some testing. I can see the page is loading for the configurable product and choosing the selections for two of the options but not the third. We have 'materials', 'size' & 'frame colour'. The default is working for the materials and frame colour but not selecting the size option.

Here is a sample of one product I have manually selected: https://fineprintco.com/untitled-1
Here is another with more 'size' selections: https://fineprintco.com/artists/alicia-beech/into-the-night

I am using a CDN but not for js.

Any help would be greatly appreciated.