I feel like a hero in this particular case, it was a bug in a code that was written when I was still too young to even read. And no one knew how to run it. We didn't have access to the pipelines so no one knew how to build it and how to run it. It was a very obscure hybrid of C and PHP. I basically had to be the compiler, I went line by line through the whole codebase, searching for the code path that caused the error. Sounds easy enough, right? Just CTRL+click in your IDE. Wouldn't it be a shame if someone decided that function names should be constructed as a string using at least 20 levels of nesting where each layer adda something to the function name and then it's finally called. TL;DR it was a very shitty code.