E-file complete! After playing with this situation a lot, it appears that the bug manifests during the review, changing $600 to $300, and you can change it back afterwards in Forms mode. In fact, for unknown reasons, after a while if I went through Review again and saw it change the number, it would say there was one error in the return, show me line 12b on the 1040 (if I recall right the location) as $300, I would type $600 in red, and after ENTER it would switch to blue, and stick around.
You can tell from the fed + state summary numbers at the top of the screen if it gets changed, or changed back. I watched our total due to the IRS remain "correct" after this point, all the way through e-filing, and the print-to-PDF copy of the return looks right also. Let's hope that's what was actually submitted.
If I have this right, I assert that my workaround is better than the one Intuit is repeating here! It left the contribution line items alone, and propagated for the state additional deduction.
