Worked on stabilizing denormalization workflows within the Symfony Serializer, focusing on resolving issues related to class discriminator mapping when allow_extra_attributes is set to false. Addressed two critical bugs in the symfony/symfony and symfony/serializer repositories, ensuring that discriminator type properties are consistently recognized as allowed attributes during object normalization and denormalization. Employed PHP and object-oriented programming principles, reinforcing each fix with comprehensive unit and regression tests across multiple normalizers. These changes improved the reliability of API payload processing, reduced denormalization errors in production, and enhanced data integrity, contributing to a more robust backend development experience for Symfony users.