If you have a Joint, Interest Bearing Account with two aliens, are BOTH flagged as 1042S reportable or is only the primary?

I would say the primary only based on the following information:Payments made to joint owners - You are required to file one Form 1042-S to report the payment made to the joint owners of that payment. If, however, any one of the owners requests its own Form 1042-S, you must provide Form 1042-S to the person who requests it in the amount allocable to that person. If more than one Form 1042-S is issued for a single payment, the total amount paid and tax withheld reported on all Forms 1042-S cannot exceed the total amounts paid to joint owners.