Calling `.catch()` on remote functions causes them to return `undefined`

[hmnd]

Describe the bug

When .catch() is called on a remote function, the function returns undefined when awaited instead of the actual returned value.

Reproduction

https://github.com/hmnd/sveltekit-rpc-catch-repro

Logs

System Info

System:
    OS: Linux 6.16 Fedora Linux 42 (KDE Plasma Desktop Edition)
    CPU: (12) x64 Intel(R) Core(TM) i7-9750H CPU @ 2.60GHz
    Memory: 11.00 GB / 31.08 GB
    Container: Yes
    Shell: 5.9 - /usr/bin/zsh
  Binaries:
    Node: 24.4.1 - ~/.local/share/mise/installs/node/24.4.1/bin/node
    npm: 11.4.2 - ~/.local/share/mise/installs/node/24.4.1/bin/npm
    pnpm: 10.16.1 - ~/.local/share/pnpm/pnpm
    bun: 1.2.21 - ~/.local/share/mise/installs/bun/1.2.21/bin/bun
  Browsers:
    Chrome: beta
  npmPackages:
    @sveltejs/adapter-auto: ^6.0.0 => 6.1.0
    @sveltejs/kit: ^2.22.0 => 2.42.2
    @sveltejs/vite-plugin-svelte: ^6.0.0 => 6.2.0
    svelte: ^5.0.0 => 5.39.3
    vite: ^7.0.4 => 7.1.6

Severity

serious, but I can work around it

Additional Information

No response