Duplicate Entry when importing addresses in V14

I’m currently importing our company data into a new installation of V14 using the Data Import tool. I tried this a few months ago with V13 and got it all working fine. However, the same data is not importing correctly into V14.

For example, if a customer has more than one shipping address, I have multiple addresses in the CSV file, each with the field “Link Name (Links)” set to the customer ID. In V13 this achieved the desired effect and the customer doc for each customer showed all the available addresses. In our V14 installation, the first address for the customer imports fine but the second and subsequent addresses are rejected with the message “Duplicate Entry”. The address is not a duplicate and all the address ID fields in the CSV file are unique.
Looking at the traceback for each failed address, I see:

frappe.exceptions.DuplicateEntryError: ('Dynamic Link', 'customer-id', IntegrityError(1062, "Duplicate entry 'customer-id' for key 'PRIMARY'"))

where customer-id is the ID of the customer that owns the address.

I’m trying to figure out whether I am doing something differently from before or if V14 is behaving differently from V13. Any suggestions would be welcome.

Sorry, I made a mistake in my post above.
I actually set “ID (Links)” to the customer ID.
I set “Link Name (Links)” to the customer name.
So the error message is:

frappe.exceptions.DuplicateEntryError: ('Dynamic Link', 'customer-name', IntegrityError(1062, "Duplicate entry 'customer-name' for key 'PRIMARY'"))

where customer-name is the customer name.

If I create two new addresses from a customer doc in the browser, they both have exactly the same contents in the link table, so clearly it is allowed.

OK, I think I found the problem.
I was providing a value for the “ID (Links)” field because it was marked as mandatory in the Data Import template for “Address”.
I have now omitted the “ID (Links)” field to let ERPNext create its own ID for the link and it now happily creates the links and imports the addresses.