Methods are not functions. If you call a method as a function, you might get the right results and you might get the wrong results. If the documentation shows you how to call a method as a method and you call it as a function and get the wrong results, that's your fault and you should stop doing it if you care about getting the right results consistently and reliably.
You should especially not file bug reports about getting the wrong results if you use the code incorrectly.
That is all.