If you edited or added any information before completing filing then this can definitely adjust your refund amount. Additionally, you may want to check your Turbo Tax fees, in the event that you inadvertently selected any add-on services; the steps are in the following FAQ: Reviewing Fees in Turbo Tax

Reducing Fees: Reducing Turbo Tax Fees

Thank you for the response but the difference is approximately $600. 

The Review asks questions and those answers could change the tax refund or amount due.  Even a box checked in the Review can change your refund amount.

I too had this issue where my refund says I was getting approximately $5,700 between federal and state. I didn’t change or review anything in a week and now it is saying my refund will be approximately $3,000. How is that possible?

VictorisD75 gives a great explanation here as to why your refund amount can change.