payment

Once a tax return has been Accepted by the IRS or a State, TurboTax receives no further information concerning the tax return or the status of any tax refund.

The IRS will be sending a letter in the next few weeks explaining the changes they made to your tax return which resulted in the lower federal tax refund.  If you disagree with the IRS explanation there will be a procedure in the letter for you to use.

If your refund was adjusted you will get a letter explaining the adjustment. TurboTax has no control over your refund once you have filed. 

Could it be for a state refund?  Federal and state refunds come from different places at different times.  At the end Turbo Tax just shows you the net federal and state combined. But that is only for your info. 

Or did you have the fees deducted from your refund?  There is an extra $40 (45 in California) Refund Processing Service charge for that. 

How to see your fees

https://ttlc.intuit.com/community/charges-and-fees/help/how-do-i-review-my-fees-in-turbotax-online/00/26353