This was still a problem for 2022 and for 2023.
The problem is that when entering the child care receipt, it posts automatically to Form ON479. BUT - it does not prompt to complete Schedule ON479-A which is where the question is about the number of supporting parents and whether one is the spouse, which is what is needed to come up with the combined income that ends up negating the credit.
ALSO - THERE IS NO WARNING! There are warnings for every ridiculous little detail, even that don't apply to us, but NO warning that Schedule ON479-A has not be completed. You shouldn't even be able to file without that being completed. So THAT is the FLAW in Turbo Tax that is causing this for all of us.
