I entered four states that paid me tax-free OID interest totaling $21.18. TT lumped them together with the State code set as MX (perhaps for Mixed?). "SmartCheck" rejects MX on the basis that it "is not a valid state ID." I am ignoring it and hope IRS doesn't reject my return. This appears to be a bug in the Smart Check code that needs to be corrected since TT changed the four states to one field as MX and Smart Check doesn't like it.
