Duplicate entries in address book

Good day, I am having trouble with entries being created for my address book when trying to select a radio button on index.php?main_page=checkout_shipping_address.

When the data fields have information in them, rather than taking the address from the radio button, it will create a new address entry from those data fields.

The weirdest thing about it : I have five separate instances of ZenCart and this is only happening on one of them.

Any insight anyone could provide would be useful. Thank you in advance.

I think I figured this out. When you have all data fields populated with input, it takes those entries and applies them to the address. Leave one or two out and it won't. We were auto-populating certain fields in one of my instances.

Thanks!