The expanded instructions for the 2025 IA 1040 Line 2 states:
Enter your federal taxable income as reported on federal 1040, line 15. If the amount of federal taxable income is zero, subtract the amount reported on IA 1040 lines 1d and 1e, and federal form 1040 line 13b from the amount reported on IA 1040, line 1c and report this amount (this amount can be negative).
Turbo tax does not appear to subract the federal form 1040 line 13b amount. This results in tax due when the amount on federal form 1040 line 13b is large enough to make IA 1040 line 2, 0
