[2.60.1] Uncaught (in promise) Symbol(obsolete)

[vladshcherbin]

Describe the bug

Async + remote functions

In reproduction repo (symbol error branch) there is cars page with derived search param and 2 remote function calls.

Page has buttons which change search param using goto function and trigger remote functions to re-run. If I:

(1) open cars page
(2) click button to trigger function re-run before they finish loading
(3) go to home page immediately

then I get an error:

Uncaught (in promise) Symbol(obsolete)

Quick recording:

Screen.Recording.2026-05-15.at.04.53.28.mov

Reproduction

https://github.com/vladshcherbin/svelte-kit-rf-bugs/tree/symbol-error (symbol error branch)

Logs

(index):1 Uncaught (in promise) Symbol(obsolete)
Promise.then
#merge @ runtime-DiICYvjG.js?v=7905ec4d:1976
#process @ runtime-DiICYvjG.js?v=7905ec4d:1891
flush @ runtime-DiICYvjG.js?v=7905ec4d:2041
(anonymous) @ runtime-DiICYvjG.js?v=7905ec4d:2180
run_all @ runtime-DiICYvjG.js?v=7905ec4d:40
run_micro_tasks @ runtime-DiICYvjG.js?v=7905ec4d:1146
(anonymous) @ runtime-DiICYvjG.js?v=7905ec4d:1155

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

No response