Got an IRS check for 55.08 the has interest applied to it. It states 12/2018 TAX REFUND 30 INT $ 1.08. I owed this year. There was no letter explaining. What do i do?

[Critter]

The letter of explanation comes a couple of weeks later but I will venture a guess ... there was a late correction in the way the underpayment penalty was calculated and the IRS is sending "refunds/rebates" of the excess paid. 

[Anonymous]

by the way the $1.08 is taxable interest income in 2019 for both federal and state. Interest paid on tax refunds is not deemed US Treasury interest exempt from state tax.