I received a 1099-B from my brokerage firm. I have a dollar amount in column 1g, but no code. Should I just not include the amount in my tax return?

As you can see looking at the "official" 1099-B:

https://www.irs.gov/pub/irs-prior/f1099b--2016.pdf

Box 1g identifies itself as a "wash sale loss disallowed."

If you enter an amount from Box 1g in the 1099-B interview TurboTax enters the amount in column 1g of Form 8949 with a code of "W" in column 1f.

Tom Young

Unfortunately for 2021, TurboTax doesn't ask for separate 1f or 1g entries. So if you do have an amount to enter for 1g and there is no code to enter into the box, TurboTax thinks that there is an error and won't proceed with the form. TurboTax needs to fix this form.