Worked on the nautechsystems/nautilus_trader repository to deliver a targeted stability fix for the serialization pipeline, focusing on the OrderBookDelta structure. Addressed a runtime panic that occurred when encountering the sentinel PRICE_UNDEF value by refining precision handling during Cython-to-pyo3 conversion and Arrow data export. Applied delta-specific precision logic to ensure that serialization used the correct value, preventing mismatches with cached precision and eliminating downstream errors. Utilized Cython and Python to implement robust error handling and data serialization improvements, ensuring end-to-end reliability along the Arrow catalog.write_data path and closing a gap not covered by previous patches.