I'm not sure if this is the exact situation you're referring to, but you do get interest sent to you if you later amend a tax return in your favor. Source: I'v

I'm not sure if this is the exact situation you're referring to, but you do get interest sent to you if you later amend a tax return in your favor. Source: I've filed a 1040X twice, both times in my favor (due to my own mistake I noticed on my own later). The IRS issued me a 1099-INT the next year for the interest they paid me. The rate was substantially above market!