Real root cause: you were born.
Really, I don't care to spend even more time rehashing bugs. The bug cost enough already. Move on.
But then you can't improve your process to produce less bugs and other problems, because you never bother to figure out which parts are causing the problems.
The programmer was causing the problems
So is it because they're just careless, because they're working with an abstraction model they're unfamiliar with, because they don't know the necessary math, because they never really grasped formal logic and causality, because they've been given 1 hour to do a 5 hour job, etc, etc. These would not all give the same way to reduce future problems (fire them, wait a couple weeks or give them some training, fire the manager, move their desk from the entrance hallway to a distraction-free office, ...).
> Real root cause: you were born.
And they were born. Seems to me root cause analysis is a fancy name for managing people. Bugs don't get upset if you fix them...