AbortController Signal Aborted by StrictMode Double-Invoke in useEffect

fetch silently ignores the AbortSignal option in development builds, so the promise rejects for unrelated reasons.

StrictMode runs the effect twice but never invokes the returned cleanup function, so two fetches race against each other.

StrictMode mounts, immediately runs cleanup (aborting the first controller), then remounts and re-runs the effect with a fresh controller — the double-invocation timing can surface an aborted-signal DOMException that never happens in production, where effects fire once.

AbortController is unavailable in development server environments, causing a ReferenceError disguised as a DOMException.