Domain Mapping on Multisite - Map every page except WooCommerce checkout

Using Multi Domains and Domain mapping plugin for our Multisite install.

We want every page of our sub-site mapped to a vanity domain... EXCEPT the checkout page. The checkout page needs to switch to the original domain because of our wildcard SSL.

Root site url = http://www.nodinxspiritstores.com
Subsite actual url = westalbanyspirit.nodinxspirit.com
Subsite vanity url = westalbanyspirit.com

We have no problems getting the vanity url working with the Multi-domains plugin. The one and only issue we have is that the exclude option in the domain mapping settings doesn't do anything. Checking the exclude box next to the Checkout page does not exclude that page from being mapped. When going to the checkout page on the front-end, it SHOULD change from westalbanyspirit.com/checkout to westalbanyspirit.nodinxspirit.com/checkout but it does not do that. It remains as westalbanyspirit.com/checkout which prevents us from using our wildcard SSL.