My son sent me his H&RBlock file to check his return before he filed.
He has tax exempt interest and tax exempt dividends. For the interest the software asked how much of it was tax exempt in his state. It didn't ask that for the dividends, though it should have.
I spent 2 hours with H&RBlock customer service before discovering that the problem was that he incorrectly said he was a part year resident of California, when he should have said he was a full year resident! Correcting that fixed the problem; apparently dividends can only be state tax exempt for full year residents.
Are tax exempt interest and tax exempt dividends treated different with respect to part year residency? Seems unlikely, but who knows...