Error: Unknown Error (No error information at all)

[Xevion]

Codecov only processed my first coverage submission successfully, and since then, has been refusing to process literally any other submission. I've tried everything from switching to a different coverage file format (lcov originally, codecov.json later), using a different branch, using a config (and then removing it), new commits, downgrading to the v4 GitHub action... Nothing works.

Here's the first and only working one:

https://app.codecov.io/github/Xevion/Pac-Man/commit/74d40a1688659762cfcd90784da2e5eda6b87d01

It's submitted twice because I opened a 'test' branch to see if it would work again if it was exactly the same, and it did.

You can see the rest of the attempts here, it's all public:

https://app.codecov.io/github/Xevion/Pac-Man/commits

None of them have worked so far. None of them include error information that I can use to diagnose the error. The upload action on GitHub Actions has never failed, and reports no useful information, even with the verbose flag. It makes no sense to me.