I usually find the issue, point it out, then they make sure they implement the fix in a way that is not alien to their codebase.

It's not many hands on one project but everyone taking care of their own projects, so it's a bit different where I'm at right now.

Some people are way better at finding issues than others, even in other's code bases.

Another good skill to have though, that is unfortunately not super duper common either, is being able to figure out and match conventions and patterns in code bases when introducing changes.