Composer: The checksum verification of the file failed

Question

I am hosting my own Satis repository via GitLab pages.

For some reason however, it keeps on erroring with The checksum verification of the file failed when composer tries to install one of the repositories.

Its happening on and off for a few weeks now, and I can't work out why its happening or how to debug it.

Here is my satis.json:

{
  "name": "Composer Repository",
  "homepage": "<snip>",
  "repositories": [
    {"type": "vcs", "url": "<snip>"},
    {"type": "vcs", "url": "<snip>"}
  ],
  "require-all": true,
  "require-dependencies": true,
  "archive": {
    "directory": "dist",
    "format": "zip",
    "skip-dev": true,
    "checksum": false
  }
}

I added checksum: false a week ago which seemed to fix the issue, but now it has just arrived again.

I've tried clearing caches and nothing is working. Any ideas?