In the California return, the Underpayment Penalty questionnaire doesn't appear unless TurboTax has tentatively calculated a penalty based on the income and payment information you entered.
In that case, you will see Underpayment Penalty listed as an item under Other Situations and you may also see a screen prompt before you get to the end of the California items asking if you want to go over the penalty section now. Respond "yes" to "Would you like to review this topic?". If yes, you are given the choice to let the Franchise Tax Board calculate the penalty and send you a bill, or complete the questionnaire.
See this FTB webpage for more information about California penalties.
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