R12.1.3 Payables: Error when adding bank account after patch

While you may upgrade to R12.1.3 and have no issues like those reported in this MOS document "ERROR PAGE ON ADDING AN EXISTING BANK ACCOUNT ON SUPPLIERS AND CUSTOMERS PAGE" via note ID 1908015.1, the details in the document show that this actually happens as a result of applying a patch to fix another issue so you could encounter this at pretty much any time!