The only situation that comes to mind when the standard deduction is changed is if the person filing a return is also claimed as a dependent on another return. In that case, the standard deduction is a calculated value based on the income being reported.
Double-check your entries in the Personal Info or My Info section of your return to be sure that you did not indicate that you are being claimed as a dependent by someone else. After you have entered your name, there is a page that asks Do any of these apply to you? On that page, there is a check-box to indicate that you are being claimed as a dependent on another return.
See this information from the IRS to learn more: Topic 551, Standard Deduction