During January 2025, Kohei Sugihara focused on stabilizing multipart upload flows in the apache/ozone repository by addressing a critical bug that caused crashes when overwriting empty files during multipart completion. He implemented a backend solution in Java that guards against null OmBucketInfo, ensuring the system handles empty-file overwrites safely. To validate the fix, he expanded automated test coverage using the Robot Framework, specifically targeting the File System Optimizer path. This work improved production stability for multipart uploads, reducing crash-related incidents and support load. His contributions demonstrated depth in backend development, cloud storage systems, and rigorous testing practices within a complex codebase.