Worked on the hibernate/hibernate-orm repository to address a bug related to duplicate attribute converter registrations in Hibernate ORM. Focused on ensuring that converters are registered only once during metadata building, this change improved the reliability and predictability of metadata construction by eliminating redundant registrations that could cause runtime inconsistencies. The solution involved modifying the registration logic and adding regression tests to validate the fix, particularly through the AdditionalMappingContributor path. Utilized Java, Hibernate, and JPA, along with unit testing, to implement and verify the changes. This work reduced potential runtime overhead and contributed to more robust ORM behavior in production environments.