TurboTax gave you the deduction you're entitled to.
see the note on the left of Form 1040 line 12, where it says, see instr. which stands for see instructions, which is what you did in a roundabout way, after the fact.
TurboTax 2020 has a lot of issues/bugs.
This is probably the least of them, even if it did confuse you for a while.
