It's implausible that TurboTax would put amounts from a single Form 1099-R on both lines 4a/b and 5a/b. The amount on line 4b and the amount on line 5b must be coming from different 1099-R forms in TurboTax.
It's also implausible that TurboTax would put anything on line 4b from a Form 1099-R that has code 7 in box 7 and the IRA/SEP/SIMPLE box not marked. The amount on line 4b must be coming from a different 1099-R form in TurboTax, one that either has the IRA/SEP/SIMPLE box marked or has code J, T, Q, N or R in box 7.
If you don't have another Form 1099-R that you can identify as the source of the amount on line 4b, perhaps it would be reasonable to delete all of the Forms 1099-R that you have entered and reenter them.
