Maybe they were talking about the program where you report tax evasion and then once the missing money is collected you get up to 30% of it? That exists.

According to https://www.irs.gov/compliance/whistleblower-office the whistleblower reward program is not available to employees of Department of the Treasury.

Sure. But during a casual chat maybe somebody mentioned that reporting tax fraud can earn you money, and then somebody else assumed that they were talking about IRS employees even though they were not.