The library that broke was something using the AWS SDK. The library stopped working with an updated version of that AWS SDK.
They experimented with different package versions and combinations of service instances to fix the issue, because they didn't know what version of the package they were using in production before the package broke for them. They got an error message about a missing function in the updated library related to streams. That led to some false guesses about the source of the error.
The conclusion is that JS is not a serious programming language like Rust or C#.
Seems like they have complex CI/CD in place, but don't conclude that they should be pushing their package lock files.
And I don't understand at all how using another programming language would have prevented this issue.