During September 2025, Celia focused on enhancing the stability of the match exit flow in the ysengoku/42-ft_transcendence repository. She addressed a bug that could cause runtime errors by implementing a defensive guard using optional chaining in JavaScript, ensuring safe access to clientState.bumper.currentAction when the bumper object might be null. This targeted fix improved reliability during competitive matches by reducing crash risk and maintaining consistent client behavior. Celia applied front-end development and game development skills, emphasizing defensive programming and code quality. Her work demonstrated a thoughtful approach to error handling, though the scope was limited to a single, well-defined bug fix.