Changing to itemized deductions increases my refund?

[hjobanpu]

TurboTax Premier states “The Standard Deduction is Right for you” and my refund is $19,013. I was curious to see what would be my refund if I would Itemized deductions (my itemized deduction of $2723 lower than standard deduction).

To my surprise, my Federal Refund increased by $3,300. I am not sure why? Can someone help me understand this. Please.

First I am shocked with this, then a bit mad and then somewhat puzzled. I have been trusting Turbotax for many years, so I start to wonder, Would this have any negative impact to my 2019 tax?

[SweetieJean]

Wait...you got a $19,000 refund? That sounds highly unlikely.

[SweetieJean]

Double check your data entry. I think you keyed something in wrong, especially commas and decimal points.

[SweetieJean]

are you subject to AMT?

[hjobanpu]

[mention://5578079 @SweetieJean] - I had double Social Security tax deduction this year (2 W2) and also I had deducted more expecting to make more in capital gain, but did not happen. I am subject to AMT. I spent time with Turbotax agent and we reviewed numbers and something to do with AMT credit is reason for higher refund with itemized deduction. Since TurboTax did not recommend to go with Itemized Deduction, this is possible defect/issue with TurboTax.