Couple ideas
Did you take a 1099R retirement IRA distribution 3 years ago and spread the taxes over 3 years? It may have transferred over like a 4th time. Delete the 1099R and form 8915. See this post for what to delete
https://ttlc.intuit.com/community/retirement/discussion/i-took-a-401k-wd-in-2019-then-spread-it-over...
One thing I can think of is if you took the First Time Homebuyer's credit and you still owe for it. But that is usually $500. Or if you got a state refund last year. That maybe be taxable.
