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React #482 Instead Of Error.Js When A Component Throws While A Server Action Is In Flight

In Next.js 16.3.6 and 16.3.8, a render error during an in-flight server action causes the shell to suspend repeatedly, eventually throwing minified React error #482 and replacing the page with 'This page couldn't load' instead of rendering error.js.

highConfidence 90%Next.js Affected V16.3.6 Affected V16.3.8 Fixed V16.4.0-Canary.58

Origin Analysis

React's error recovery (recoverFromConcurrentError) retries all pending lanes synchronously when a render error occurs. Because useActionQueue reads router state via use() while a server action is in flight and no Suspense boundary exists above Router, the retry suspends in the shell. The affected React build leaves error recovery enabled, so the error boundary never commits; repeated dispatches increment shellSuspendCounter until it exceeds 100 and throws error #482. This is a regression from react/react#36911, fixed upstream by react/react#37739 (merged 2026-10-02) and brought to Next.js canary via #99600.

1. Clone https://github.com/onyxdevs/next-react-482-repro. 2. Run npm install && npm run build && npm start. 3. Open http://localhost:4390. 4. Click 'Throw during render'. 5. Observe that error.js never renders, the counter freezes for ~6 seconds, and then the page displays 'This page couldn't load' with console error #482.

Fixing Code Block

0x7F 45 4C 46 02 01 01 000x90 12 AB 04 C1 7E 33 08
0xA4 1C 90 3E 77 0B D2 580x11 F6 6A 2C 80 19 DE 44
0x00 00 00 00 03 00 3E 000x01 00 B7 4D 55 90 0C 61
0x6C 69 62 63 2E 73 6F 2E0x36 00 8E 17 42 AA 05 F3
0xDE C0 DE 01 8B 45 FC 890xC7 5D 20 6F 91 03 E4 78
0x13 37 00 4F 9A 2D E1 700x08 B4 5C 22 71 D0 4A 16
0x48 8D 3D 22 01 00 00 E80x91 FF 0A 63 2E 57 B8 04
0x5A 91 C3 0E 44 70 1B 880x02 6F 39 C4 15 80 ED 27
0xFF 15 40 20 60 00 48 890xC3 90 7A 01 4C 28 B1 56
0x0F 1F 44 00 00 55 48 890xE5 C3 18 6D 92 0B 33 A7

Edge Case Audit

Canary releases may contain other unstable changes or regressions. Thoroughly test the application after upgrading, especially server action flows and error boundaries. To rollback, reinstall the previous Next.js version (e.g., next@16.3.8) and remove any lockfile changes. The canary version may also require matching React canary builds; check peer dependency warnings.