Same issue

This warning in TurboTax often occurs due to a data entry error where the same amount is mistakenly entered in both Box 18 (Tax Deducted) and Box 19 (Gross Amount). Box 18 should only contain the tax deducted, while Box 19 contains the total OAS received, causing a validation error if both are identical.

Ensure Box 18 reflects only the tax deducted, which is typically a much smaller amount than the total OAS benefit, not the same figure as Box 19.

If you have amounts in Box 20 (lump-sum payments), ensure they are entered correctly, as these can also trigger verification limits.

Double-check your actual T4A(OAS) slip to ensure the amounts were not transposed.

If the error persists, delete the T4A(OAS) entry entirely and re-enter the data carefully. 

Try these above troubleshooting steps, and if the issue persists, contact our phone support so they can screen share and investigate.

Thank you for choosing TurboTax. 

I don't believe the info provided by the moderator is correct.  CRA website clearly says to enter amount from box 18 which is taxable amount paid. Tax deducted is in box 22.

In any case, the warning is no longer there following today's update  March 5 2026.

Thank you for responding however.