Svelte boundary doesn't catch form error

[timootten]

Describe the bug

This is my code:

+page.svelte

<script lang="ts">
    import { runTest } from './test.remote';
</script>

<h1>Landing Page</h1>

<svelte:boundary>
    {#snippet pending()}
        <p>Pending</p>
    {/snippet}
    {#snippet failed(error, reset)}
        <p class="text-red-600">Failed to runTest</p>
        <p class="text-red-600">Error message: {error}</p>
        <button onclick={reset}>Try Again</button>
    {/snippet}

    <form {...runTest}><button type="submit">runTest</button></form>
</svelte:boundary>

test.remote.ts

import { form } from "$app/server";
import { error } from "@sveltejs/kit";

export const runTest = form(async () => {
  error(500, "This is a test error from test.remote.ts");
});

Result is in the images, it only displays:

500
This is a test error from test.remote.ts

Reproduction

https://github.com/timootten/SvelteKit-Form-Error

Logs

  VITE v7.2.0  ready in 1548 ms

  ➜  Local:   http://localhost:5174/
  ➜  Network: use --host to expose
  ➜  press h + enter to show help

System Info

System:
    OS: Windows 11 10.0.26100
    CPU: (16) x64 AMD Ryzen 7 5700X 8-Core Processor
    Memory: 14.07 GB / 31.91 GB
  Binaries:
    Node: 22.20.0 - C:\Program Files\nodejs\node.EXE
    npm: 10.9.0 - C:\Program Files\nodejs\npm.CMD
    pnpm: 10.18.1 - C:\Users\timoo\AppData\Local\pnpm\pnpm.CMD
    bun: 1.3.1 - C:\Users\timoo\AppData\Local\pnpm\bun.CMD
    Deno: 2.3.3 - C:\Users\timoo\.deno\bin\deno.EXE
  Browsers:
    Chrome: 141.0.7390.123
    Edge: Chromium (140.0.3485.54)
    Firefox: 144.0.2 - C:\Program Files\Mozilla Firefox\firefox.exe
    Internet Explorer: 11.0.26100.1882
  npmPackages:
    @sveltejs/adapter-node: ^5.3.2 => 5.4.0
    @sveltejs/kit: ^2.43.2 => 2.48.4
    @sveltejs/vite-plugin-svelte: ^6.2.0 => 6.2.1
    svelte: ^5.39.5 => 5.43.3
    vite: ^7.1.7 => 7.2.0

Severity

blocking an upgrade

Additional Information

No response