Our last name is seperated, i.e. xx yyyyyyyy. Normally TT handles this correctly but in the form 1099-INT worksheet, at the very bottom, in the "Recipient's address and zip Code" the xx part of our last name was used for the state code which generated an "Illegal zip code error". I finally realized that the state code was wrong and fixed it. So all good but... didn't notice that my wife's last name was now incorrect. Hopefully this will not generate an error with the IRS.
I'm guessing that is might be a problem for others in a similar situation.