Finding the cause of that unexpected issue is my specialty, @mikeconstien60.

Have you first pick a name in the Drop Ship to field before creating a new Ship to address? Or do you create first a Ship to address before selecting a name in the Drop Ship to box? 

When creating a Purchase Order (PO) in QuickBooks, you'll need first to select a name in the Drop Ship to field before adding a Ship to address. This will prevent creating a new inventory site. 

This way, the added ship to address will only show on the name's profile. In the example, the added ship to address was only assigned to the customer's Address info. 

On the other hand, if you add first a new address in the Ship to field before selecting a name in the Drop Ship to box, this will result as if you create a new inventory site. 

For more information, please check this article: Create purchase orders in QuickBooks Desktop.

Also, to get an overview of your purchase history and keep track of outstanding orders, you may pull up the Open Purchase Orders report. Here's how:

1. Go to the Reports tab.
2. Select Purchases.
3. Click Open Purchase Orders. 

Let me know how this goes and leave a reply below if you have further questions about adding a ship to address in PO. I'm always around to help you. Have a good one.