derived_inert warning with unfinished remote function

Describe the bug

Async + remote functions

In reproduction repo there is cars page with a simple remote function call.

This function is delayed by 3 seconds. If I go to other page while the remote function is not finished, I get derived_inert warnings.

Quick recording:

https://github.com/user-attachments/assets/59fa37f7-b74c-41a0-93da-b0a635e3259a

Reproduction

https://github.com/vladshcherbin/svelte-kit-rf-bugs

Logs

<details>
 <summary>Browser Log</summary>

[svelte] derived_inert  client.js?v=89ae070d:3356
Reading a derived belonging to a now-destroyed effect may result in stale values
https://svelte.dev/e/derived_inert
warn @ client.js?v=89ae070d:3356
derived_inert @ warnings-Cm7Lh8j-.js?v=89ae070d:46
execute_derived @ runtime-CHnyNzb0.js?v=89ae070d:3371
update_derived @ runtime-CHnyNzb0.js?v=89ae070d:3397
get @ runtime-CHnyNzb0.js?v=89ae070d:5077
(anonymous) @ query.svelte.js?v=89ae070d:107
Promise.then
(anonymous) @ query.svelte.js?v=89ae070d:107
setTimeout
(anonymous) @ client.js?v=89ae070d:2732
requestAnimationFrame
navigate.type @ client.js?v=89ae070d:2731
(anonymous) @ client.js?v=89ae070d:2730

</details>

System Info

System:
    OS: macOS 15.7.5
  Binaries:
    Node: 26.1.0 - /Users/shcherbin/.local/state/fnm_multishells/17968_1778803213963/bin/node
    pnpm: 11.1.2 - /Users/shcherbin/.local/state/fnm_multishells/17968_1778803213963/bin/pnpm
  Browsers:
    Chrome: 148.0.7778.168
  npmPackages:
    @sveltejs/adapter-node: ^5.5.4 => 5.5.4
    @sveltejs/kit: ^2.60.1 => 2.60.1
    svelte: ^5.55.7 => 5.55.7
    vite: ^8.0.7 => 8.0.12

Severity

blocking an upgrade

Additional Information

[!IMPORTANT]
Additionally on page change unfinished remote function is not terminated and if I come back to page the new one takes more time to finish (e.g. 5s instead of 3s).

Start with the linked reproduction repository and its src/routes/cars/+page.svelte page, then reproduce the delayed remote-function call while navigating away. Use the browser log and the query.svelte.js/client.js stack references to trace the warning and unfinished request; done means navigation no longer produces derived_inert warnings and the abandoned request is terminated.