Subject: Issue in opting Old vs New Tax Regime due to delay in filing ITR (AY 2025-26)

I am facing a practical issue regarding selection of tax regime for AY 2025-26.

Facts of the case:

1. In AY 2024-25, the assessee had business income and was subject to tax audit.
2. The assessee opted for Old Tax Regime by filing Form 10IEA within the due date (filed on 07/10/2024).
3. For AY 2025-26, the assessee is NOT liable for tax audit (non-audit case).
4. However, the ITR for AY 2025-26 could not be filed within the due date and now needs to be filed after the due date (belated/updated return).

Issue:

- As per provisions of Section 115BAC, once the assessee opts out of new regime (via Form 10IEA), the option continues for subsequent years unless withdrawn.
- However, since the due date for AY 2025-26 is missed, the system is not allowing filing under Old Tax Regime.
- At the same time, portal is detecting previous Form 10IEA and creating validation conflict.

Query:

1. In this situation, is the assessee mandatorily required to shift to New Tax Regime for AY 2025-26 due to delay in filing?
2. Whether the earlier option exercised via Form 10IEA (AY 2024-25) becomes ineffective due to delay in current year filing?
3. Is there any legal or practical way to continue with Old Tax Regime in AY 2025-26 in such case?

Any guidance with relevant section/rule reference or practical experience would be highly appreciated.

Thank you.