If an undefined class method is called via call_user_func_array(), the ZE2 __call() handler won't catch it.

class test
{
  function __call($method,$args)
  {
    print "test::__call invoked for method '$method'\n";
  }
}
$x = new test;
$x->fake(1);
call_user_func_array(array($x,'fake'),array(1));

Output:
test::__call invoked for method 'fake'
Warning: call_user_func_array() [function.call-user-func-array]: First argumented is expected to be a valid callback, 'test::fake' was given in /usr/local/book/book/catalog/classes/bug.php on line 11