After I received the letter from the IRS, I went back to Turbo Tax to see if I missed a step. I went through the updates (maybe something had changed after I filed), and it kept referencing to 2019 income, which I don't understand why 2019. I researched this more on the IRS website after receiving the letter, and there is NO reference regarding 2019 income. The only reference is Publication 596, which is also stated within the IRS letter. I've used Turbo Tax for many, many years filings, but I will be disappointed if I do end up receiving this $1,501.00. I think I'm going to trust the IRS more than Turbo Tax.
