I can't see your 1099-B so I have no idea how the trade was reported to you, really. But it sounds like TurboTax only recognized as "proceeds" the cash and, since you reported no basis, limited the gain to that.
But I assure you that TurboTax is not making any "judgements" about how the transaction really should be reported to the IRS. It's completely dumb with respect to cash plus stock deals.
