Can Shopify auto-switch between two unconnected domains?

The Shopify Store I’m dealing with has two domains - the Primary Domain (shop.xxxxxx.com) is not connected, the second Domain (xxxxxx.myshopify.com) is an Alias. We want it to stay like this for outside redirect reasons. Is there any point that Shopify will see this as an issue and fallback to the other domain to try to correct it? ex: changing that Alias to the Primary Domain without user input.

If it’s currently working with that setup, then there’s no reason that Shopify would manually stop it on you. That’s a pretty weird way to handle things though – I wouldn’t recommend it.