Letter 6419 AdcCTC Child Tax Credit - the repayment protection income limits are different on the letter than they are on the IRS website and IRS Fact sheet.

Letter 6419 Repayment Protection MAGI modified adjusted gross income limits - 60,000 married,  50,000 HOH, 40,000 single
IRS website:
You won’t qualify for any repayment protection if your modified adjusted gross income (AGI) is at or above the
amounts listed below based on the filing status on your 2021 tax return.
• $120,000 if you are married and filing a joint return or if filing as a qualifying widow or widower