The generated code can be easily regenerated. Delete the generated code file, and then right click on the feature in the "Solution Explorer" window. In the context menu which appears select the entry "Run Custom Tool", this will regenerate the code file.
You definitely should not modify the generated files, nor should you have any reason too.
I have had few problems with these files. Occasionally in work these files might get out of sync if multiple people are working on them, but regenerating them using the solution above usually alleviates any problem.