Inherited and unimplemented method of a class

Hello folks.

An inherited and unimplemented method of a class in PHP-5.2.5 gets called twice:

class Foo {
	public function foo() {
		echo get_class($this);//or __CLASS__;
	}
}
class Bar extends Foo {
}
$f = new Bar;
$f->foo();

Shouldn't it be only once? If I'm doing something wrong, how would I
do it right? If it's a bug, did it get fixed as of 5.2.6RC5 ?

Thanks.