Why won't Instagram allow product tagging from my linked domain?

[escootershop]

Hi,

We have linked our shopify store to Facebook/Instragram as a store 

The issue we are having at present is shopify is pushing top level domain IE one.com as the "base url" to facebook so products in the catalog are mapped to a url of one.com/products/rice

Both one.com and one-com.myshopify.com/admin are verifed domains on FB.

The only issue is Instagram won't let us select a product to tag as it is not on the same domain.

This is temporarily fixed by changing the individual prouct url on each product to one-com.myshopify.com/admin/product/rice etc

It reverts back to the old URL over night and is very time consuming to constantly change it.

Any idea what I am doing wrong?

Many thanks in advance