Describe the bug

After a recent npm update (which I'm assuming updated Svelte, but correct me if I'm wrong), I've started getting a 404 error when attempting to do a release build. It doesn't happen when I do a preview build (see attached image).

My site is a very simple static webpage (using adapter-static). No stub routing, no spaces in image filenames, etc.

Reproduction

See files I've attached here. Since this error occurs at build time (and not during website usage), I'm not sure how to respond to this.

My website is proprietary and thus not on Github. I can send the full repository to a Svelte maintainer via ProtonMail if necessary. Please advise.

Logs

I'm not sure what logs to include. If you need any, please advise. Thank you in advance for your help...

System Info

System:
    OS: Linux 5.10 Ubuntu 18.04.6 LTS (Bionic Beaver)
    CPU: (4) x64 Intel(R) Core(TM) i7-6500U CPU @ 2.50GHz
    Memory: 3.90 GB / 6.08 GB
    Container: Yes
    Shell: 4.4.20 - /bin/bash
  Binaries:
    Node: 16.4.1 - ~/.nvs/node/16.4.1/x64/bin/node
    npm: 7.18.1 - ~/.nvs/node/16.4.1/x64/bin/npm
  npmPackages:
    @sveltejs/adapter-static: ^1.0.0-next.13 => 1.0.0-next.21
    @sveltejs/kit: next => 1.0.0-next.201
    svelte: ^3.34.0 => 3.44.2

Severity

blocking an upgrade

Additional Information

No response