GTIN is required for product...be we HAVE them

Not sure what I’m doing wrong here. I keep seeing the following:

All of our products have GTIN numbers in Shopify. They also have the Google Product Category selected. Furthermore, they are all listed as active in the Google Merchant Center, where the GTIN numbers are also listed.

What on earth am I missing here folks?

Thanks advance!

If you are using the free shopping app, this is currently bugged for several weeks now. I recommend you use a different app, or continue to communicate with Shopify.