Worked on stabilizing the Material system within the Babylon.js repository by addressing a critical bug and enhancing code safety. Focused on TypeScript, the developer corrected a callback reference in the Material class, renaming Material._MiscDirtyCallBack to Material._PrePassDirtyCallBack to ensure proper functionality. Additionally, they improved the reliability of decorator logic by introducing optional chaining when accessing this[key], which prevents runtime errors caused by undefined values. The work centered on bug fixing and refactoring, contributing to more robust scene management and reducing the likelihood of runtime issues in Babylon.js projects that rely on the Material system’s stability and safety.