When TT runs "Smart" Check, it flags the 8-state 1099 INT with the MX error which appears in the form in the line " State ID where exempt interest was earned. If more than state, see Help." I wernt to Help, and it didn't help.
The problem is, I earned the interest FROM those states not IN them.
In another 1099 INT muni in my return from a single statew, the form for that line shows XX.
This indicates to me the code is buggy - multiple states show MX; single states show XX.
