Why won't my new product size variant save on Shopify?

[greenstemstodd]

Hey!

I'm setting up a new shop that has not been launched. Our products have variant options for shape, colour and size. All were entered and saved weeks ago.

Recently we added a new size to our products. It's the smallest size and should appear first. Since the variant is new it is automatically added to the bottom of the options list. I have tried to drag and drop the variant like all Shopify how-to posts explain. When I do this, I hit done and the variant stays on top of the list but when I hit save for the full product that variant drops back down to the bottom. 

I have reorganized the shape variants in the same way - drag, dropping, done, save. It works. It's the size variants that will not save.

What is weird is that after I hit save the product save pop up happens and then when I try to leave the page a pop up comes up saying the changes I've made to the page will not be saved. This only happens with the size variants.

What's up?