This bug applies to both taxpayer and spouse (separately).
I thought of one other workaround that will cause TurboTax to carry forward the correct amount of basis and doesn't involve overrides. Simply indicate that all but $1 was QCD. This will cause TurboTax to properly prepare Form 8606 and to produce the correct carryforward on line 14 which will propagate to the IRA Information Worksheet. The side-effect will be that either $1 of basis will be consumed or $1 of the distribution will be taxable, and Form 8606 will be included with the tax return. Still not great, but it works. Generally speaking, there is nothing wrong with not treating some amount transferred to charity as not being QCD; treating a QCD-compliant distribution as a QCD is optional.
