On my amended tax return, my taxable income increase from $12,968 to $19,496. Shouldn’t the new tax liability be $2132 and not $2847? Turbotax software calculated that.

Save a PDF of the amended return and look at what changes there are in column B and also review the new 1040 that was populated against the original 1040  to see what changed ... it may not have been only federal taxes. 

The tax table is only one of seven different methods that can be used to calculate your tax, depending on what is in your tax return. Your tax return might require one of the other methods. And something you changed in the amended return could mean that the amended return has to use a different calculation method than the original return. On your Form 1040-X, line 6 should have an abbreviation on the left side that shows what method was used to calculate the tax on the amended return. What does it say?

Also, as Critter-3 suggested, there might be other taxes besides regular income tax. On Form 1040-X, what are the exact amounts in columns A, B, and C on line 6 and on line 11?

did you add self-employment (1099-NEC) income into the amendment.

if yes, there is also the self-employment tax on top of the income tax. 

what form did you add for the amendment? 

look at Schedule 2

I’ve figured it out I didn’t see the additional taxes added from the overpayment on the 1095 A premium tax credits