How do I file an amended prior year return to reflect a carryback foreign tax credit (both standard and AMT)?

TubroTax Online 2025 version as of February 14 2026 is saying I have to amend my prior year return to reflect my new AMT election for simplified calculation of foreign tax credit, which I have maxed out for tax year 2025. I do not understand why the 2024 return must be amended and the credit cannot carry forward to 2026 (though I will be paying more foreign tax probably over the limit in the coming year).