@jdub_SD
"and which version of turbo tax asks that question??"
You need to pay up to the Premier version of TurboTax in order to get the ESPP "guided" interview for the sale of the stock. You won't have to upgrade as you certainly can get your stock sales correctly entered using the "plain vanilla" 1099-B stock sale interview since the broker has given you the correct basis to use in that supplemental information. But maybe you'll want to upgrade anyway, depending on your situation.
If you don't upgrade you'll simply enter your sales exactly as they read on the 1099-B and then use the process TurboTax has in place to, in effect, state "the 1099-B reported by the broker is incorrect, so here's the correct basis."
In your original post you said "The ESPP shares were acquired at a 10% discount in 2017. I do not believe I ever had this discount appear as income on any W2."
With shares acquired via an ESPP it's the sale of the stock that can generate reportable compensation income, so if your sale did create compensation income - which I'm guessing is the case here - and that income didn't show up on a W-2, then in addition to entering your stock sale you'll also need to enter the compensation as an addition to your ordinary income. (ESPP-related compensation is typically reported in Box 14 of the W-2 but it's not uncommon for employers to not report this compensation in the case of "Qualified Dispositions", which could, possibly, be your situation.) Using the ESPP guided interview if you upgrade will post this compensation income if you go to the very bitter end of the "Stocks, Mutual Funds, Bonds, Other interview. You can't simply stop the interview when you're done entering your sales information.
However, there's other ways of getting the compensation entered into your income tax return that don't
