Why BufferSize is not working in this case ?

<img width="1261" height="1105" alt="Image" src="https://github.com/user-attachments/assets/d5f38ea5-f541-4b90-be21-9f979d2acefd" />

When a feature is bigger than the tile (and the tile is fully covered by it), even with a BufferSize of 0, the rendered feature is still bigger than expected. How can I avoid this and strictly limit rendering to the tile bounds?