I was stuck too, I am an expert. I found a fix--instead of simply editing the WTH to wth, just DELETE the whole state line in the W2 form. Then I ran a review to make sure return was error free, it was. Next I went back to the W2 form and re-entered the state line replacing the last part of the state ID "WTH"" with "wth", it worked and the return is error free.
