[5.43.13] Hover preload error: `props_invalid_value`

[sillvva]

Describe the bug

I'm getting the following error:

error.svelte:28 Svelte error: props_invalid_value
Cannot do `bind:value={undefined}` when `value` has a fallback value
https://svelte.dev/e/props_invalid_value

I'm not 100% sure, but I am guessing that it is caused by having the same component (in my case a <Search> component) on two pages with a binding that is dependent on async data.

The error is generated when hovering a link from one page to the other while hover preloading is enabled.

Reproduction

https://stackblitz.com/edit/sveltejs-kit-template-default-j4cmhsez?file=package.json,src%2Froutes%2F%2Bpage.svelte,src%2Froutes%2Ftest%2F%2Bpage.svelte

Hover the link and check the browser console

Logs

System Info

System:
    OS: macOS 26.1
    CPU: (16) arm64 Apple M4 Max
    Memory: 309.19 MB / 48.00 GB
    Shell: 5.9 - /bin/zsh
  Binaries:
    Node: 24.11.0 - /Users/sillvva/.nvm/versions/node/v24.11.0/bin/node
    npm: 11.6.1 - /Users/sillvva/.nvm/versions/node/v24.11.0/bin/npm
    pnpm: 10.21.0 - /Users/sillvva/.nvm/versions/node/v24.11.0/bin/pnpm
    bun: 1.2.20 - /Users/sillvva/.bun/bin/bun
  Browsers:
    Firefox: 144.0
    Safari: 26.1
  npmPackages:
    svelte: 5.43.13 => 5.43.13

Severity

blocking an upgrade