The 1099INT is income for 2018 and you will need to Amend the 2018 return to report this income.
You have to wait until the original return is processed and you get your refund.
Then approx February 22nd, TurboTax will have the Amended process for 2018 returns ready.
You will then log back into your TurboTax account and Amend the 2018 return, adding whatever was left off the original return.
