Experienced the same problem .. only the first account listed is imported. Marcus issues multiple 1099-INTs in a single document. So you cannot use import in this case. As long as the multiple 1099-INTs are from the same Payer TIN, they can be totaled and entered as one 1099-INT. Marcus does not provide a total for you.
Also, the imported data says FATCA YES which causes the FATCA box on 1099-INT to be checked. The FATCA box is NOT checked on the 1099-INT, so this is incorrect.
