New ID &1 being added

What causes this issue?

During maintenance of the bank details, a bank details ID was specified
for the business partner that does not yet exist.

System Response

A new bank details ID is being added to the bank details of the
business partner.

How to fix this error?

If necessary, delete the old ID via full maintenance or by deleting all
fields except the bank details ID.

Error message extract from SAP system. Copyright SAP SE.