In February 2025, Alex Grebe focused on improving the numerical stability of the PCG solver in the lattice/quda repository. By deferring the initialization of the x_update_batch variable until after validating the residual_type parameter, Alex addressed a bug that previously led to NaN residuals during high-precision simulations. This targeted fix required careful low-level debugging and a strong understanding of numerical linear algebra and parameter-driven code paths in C++. The work enhanced solver reliability across diverse configurations, reducing the risk of misleading results in downstream analyses and contributing to the overall maintainability and correctness of the scientific computing codebase.