Worked on the godotengine/godot repository to improve the stability and correctness of ImmediateMesh by addressing a nuanced edge case in 2D and 3D vertex handling. Focused on refining the surface initialization logic, the developer reset the vertex_2d flag when starting a new surface, preventing the mixing of 2D and 3D vertices and eliminating misleading error messages. This targeted bug fix, implemented in C++ within a game development context, enhanced code reliability and reduced debugging time for rendering issues. The contribution directly improved rendering correctness and developer experience, demonstrating careful attention to detail and a methodical approach to code quality.