Why does the Fetch() method in an arbitrary php code of the Bitrix24 business process not return false?

Question

1C-Bitrix

Why does the Fetch() method in an arbitrary php code of the Bitrix24 business process not return false?
The same method, if used not in a Business process, but simply in a php file, works as it should - if there is no data, it returns false.

$rootActivity = $this -> GetRootActivity();
$em = $rootActivity->GetVariable("EMAIL_WORK"); 

$rs = CCrmFieldMulti::GetList(
  array(),
  array(
  'ENTITY_ID' => 'LEAD',
  'VALUE' =>$em ,	
  'COMPLEX_ID' => 'EMAIL_WORK' 
  )
    );

  
  if ($rs->Fetch()) {
  
              $rootActivity->SetVariable("isDubleCQ",1); 

              }  else {
 $rootActivity->SetVariable("isDubleCQ",0); 
}

Answer 1

It seems to me that the problem is not in the fetch method. The main question is what is in the $em variable at the time the elements are found.
You know that if $em = true, it's the same as $em = 1, but if $em = false it won't find anything.
After assigning $em, add the following code:

ob_start();
echo "<pre>";
var_dump( array(
  'ENTITY_ID' => 'LEAD',
  'VALUE' =>$em , 
  'COMPLEX_ID' => 'EMAIL_WORK' 
));
file_put_contents($_SERVER['DOCUMENT_ROOT'].'/test_bp_val.txt', ob_get_clean(), FILE_APPEND);

And understand why it returns a particular value