Worked on stabilizing the IntersectionObserver integration within the facebook/react-native repository, focusing on resolving a regression that affected UI visibility tracking. Addressed a critical issue by reverting the Shadow Node cleanup logic executed after unobserve, which had previously led to unintended deletions from internal maps and instability for downstream applications. This rollback restored reliable behavior for components relying on IntersectionObserver, reducing maintenance risk and preventing further regressions. The work demonstrated careful debugging and precise change management, utilizing JavaScript and Web APIs to ensure robust integration. No new features were added during this period, with efforts concentrated on targeted bug resolution.