Why would my tax owed go way down when I enter $4000 worth of household charitable donations if I'm taking the standard deduction? Is this an error in turbotax?

Turbotax tells me that I should take the standard deduction since I don't have enough donations. So then I deleted the charitable donations, but my tax owed went up considerably. So entered it back in, but it went down. I only have about $3k of other deductions, so this doesn't make sense. This is not the $300 that the irs allows for cash contributions.

posted

In 2021, even taxpayers who take the standard deduction are allowed a $300 deduction for cash charitable contributions, or $600 if married filing jointly. This law does not apply to any future years.