Saving PHP Settings in WHM wrote the configuration correctly but returned a 502 to the browser, and the page then showed stale values.
Cause
The save reloaded PHP-FPM synchronously, which restarted the worker handling the admin’s own request before the response and the saved settings could finish.
The fix
The write and validation step now stops before the reload, and the reload became a separate step. A first attempt scheduled the reload right after the response, which still caused a brief 502 on the redirect that followed. The final version queues the reload as a delayed background job so it never overlaps the request that triggered it. A failed reload is logged and never turns a successful save into an error.
Verifying
New tests cover the write, the separate reload and the delayed dispatch (2572/2572). On the development server we confirmed the redirect and next page load succeeded with the saved value, and that PHP workers restarted shortly afterward.