Why is my refund less than what TurboTax said I was getting back?

Does the IRS website indicate that you were sent less than what was reported on your federal tax return Form 1040 Line 34? - https://www.irs.gov/refunds

It depends. If you have a discrepancy between your return and your refund, it may be caused by a refund offset or a correction made on your return. 

A refund offset is when the government applies part or all of a taxpayer's refund towards the taxpayer's past-due income tax, child or spousal support, student loans, or state unemployment compensation debts. If this happens, you should get a letter from the government explaining why you didn't get the entire refund. You can also get this information by looking up your refund at the IRS Where's My Refund page, as stated by @DoninGA.

The IRS may have also made a correction to your tax return, resulting in a lower than anticipated refund. Again, you'll get an official explanatory letter when this happens. Common corrections for the 2021 tax year involve Line 28 (Child Tax Credit) and/or Line 30 (Recovery Rebate Credit). If these credits were taken in error, the IRS will automatically adjust your return to disqualify you from the credit amount.

@Wendy192