nextjs - 💡(How to fix) Fix router.replace with shallow: true persists shallow flag in history state, causing getServerSideProps to be skipped on browser back navigation

Link to the code that reproduces this issue

https://github.com/JanKaifer/next-repro-34365.

To Reproduce

When router.replace is called with shallow: true, Next.js writes the shallow flag into the window.history state of that entry. This is correct for the immediate navigation, it suppresses the getServerSideProps call as intended. However, the flag is never cleared, so when the user later navigates back to that entry via the browser, Next.js reads the flag from the history state and incorrectly skips the data fetch again. The page URL updates but the page is rendered with stale data.

Current vs. Expected behavior

Expected behaviour

Navigating back to /page1?count=1 via the browser should trigger a getServerSideProps call and render fresh data.

Actual behaviour

getServerSideProps is not called. The URL updates to /page1?count=1 but the page retains stale data from the previous render.

Provide environment information

n/a

Which area(s) are affected? (Select all that apply)

Linking and Navigating, Pages Router

Which stage(s) are affected? (Select all that apply)

next dev (local), next build (local), next start (local), Vercel (Deployed), Other (Deployed)

Additional context

Related issues

This appears to be a variant of #34365 and #16028.