Timely paid all of my 2017 California Estimated Taxes that TurboTax calculated and specified on my 2016 return. I'm filing 2017 taxes now and have underpayment penalty?

Let's make sure you entered your California estimated taxes first.  TurboTax does not transfer this information because they don't know for sure that you made the payments.

Enter any federal, state or local estimated tax payments you’ve made under Estimates, in the Estimates and Other Taxes Paid section. You'll find this section in Deductions & Credits under either the Federal Taxes tab or the Personal tab, depending on the product. For a shortcut, type “estimates paid” in the search box and use the “Jump to” link.

Continue to review and confirm the estimated payments have been entered.

If after checking this, and if they were already entered, compare the 2016 and 2017 Forms 1040 to see the differences in income, adjustments, deductions and payments. Example: Did his income increase? Did you lose deductions or credits?