I had this same issue.
Here is my theory as to why it is actually OK for me. Last year, I wanted to take the standard deduction, but then TurboTax recommending itemizing even though the deduction was slightly less than the standard, but then on top of that I got this line 9b reduction in NIIT that made me get a bigger refund.
This year, the standard deduction got bigger, so for me it is just flat out better, even without line 9b.
My understanding is that you can only fill in 9b if you itemize. You could test this on your return by changing between itemized and standard.
