I believe you only put the interest amount in box 3, not box 1. You can manually enter it without the 1099Int. But if you do get a 1099 make sure it is the same amount in the same box. You can put US Treasury or just I Bond interest as the payer.
Or where did you cash it in? I cashed in a bunch of bonds at Wells Fargo and was surprised WF sent me a 1099Int. So I put Wells Fargo as the payer.
