Since the difference is exactly $1,400 it looks like you told TurboTax that you did not receive the third stimulus payment, so TurboTax gave you a Recovery Rebate Credit of $1,400 on your tax return. But you actually did receive the stimulus, or at least the IRS sent it to you, so you are not entitled to the credit on your tax return. Therefore, the IRS adjusted your tax return by removing the credit. The Recovery Rebate Credit is on Form 1040 line 30. The IRS will send you a letter in a couple of weeks telling you what they changed. See the following links for additional information.
Why is my refund direct-deposit or check lower than the amount in TurboTax?
Why is My Tax Refund Not What I Expected?
