Stale values when navigating from within a boundary #16207

Describe the bug

When navigating from within a boundary the route sees stale values.

Reproduction

SvelteLab

1. Click Go
2. You should see 1, you will see Uncaught TypeError: can't access property "y", (intermediate value).x is undefined in the console.

Switching to {#await block does work every time, await tick() does not help, flushSync does not help, setTimeout helps.

If it does not reproduce, try to refresh with the Refresh button on the main route, it's quite inconsistent in the repro but you can hit it.

Logs

Uncaught TypeError: can't access property "y", (intermediate value).x is undefined

System Info

N/A

Severity

annoyance

Additional Information

No response