We can’t be afraid to change code. If your code change caused a production issue, what’s stopping someone else from causing a similar issue even if they aren’t refactoring?

I have worked on teams where people don’t know what the code does and the test coverage is spotty. It’s a minefield and only a matter of time before something breaks. It sounds like your refactoring work was a much needed step in the right direction.

There needs to be sufficient testing and monitoring in place to catch problems earlier than production, so that people are not afraid to change code.

Would you be willing to share more details about the specific problem you ran into?