AI & Agent Dev Bug Sandbox Back to Radar

`Scroll: False` Not Preserved Across Async PPR Retry Navigations (Force-Dynamic Pages)

On force-dynamic pages using PPR, router.replace(url, { scroll: false }) loses the scroll:false option when an async retry navigation occurs due to a tree mismatch. The server-patch reducer hardcodes scroll-to-top, causing the page to jump to the top on every query parameter change after a prefetch has populated the optimistic route cache.

highConfidence 92%Next.js Affected V16.1.6 Affected V16.3.0-Canary.52

Origin Analysis

server-patch-reducer.js hardcodes ScrollBehavior.Default on retry navigation, so the original scroll:false intent from router.replace is never threaded through the async retry path.

1. Build and start the reproduction app in production mode: npm i && npm run prod 2. Open http://localhost:3000 3. Scroll down to the Filters section at the bottom 4. Tick one colour checkbox — the page scrolls back to the top.

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

This patch modifies dist/ files directly, so it will be overwritten on any rebuild or package update; apply via patch-package or move to source. If scrollBehavior is undefined for older cached actions, the fallback keeps previous behavior, but test concurrent navigations to ensure no stale scrollBehavior is applied across different retries. Rolling back to an unpatched Next.js version will reintroduce the bug; pin the patched version until an official fix lands. Also verify that gestures and hard retries still behave correctly when scrollBehavior is explicitly set.