Description:
------------
The result of this equation (echo 240 / 23;) is NAN in each occurrence when I run DateTime class before the equation. The datetime class needs to be run multiple times to get the NAN result (for ($a=0;$a<2;$a++){). 



Test script:
---------------
for ($a=0;$a<2;$a++){
	$lastResponse = date("Y-m-d");	
	$noResponse = date("Y-m-d");	
	$dateCreated = new DateTime(date("Y-m-d", strtotime($lastResponse)));
	$dateNotCreated = new DateTime(date("Y-m-d", strtotime($noResponse)));
	$today = new DateTime(date("Y-m-d"));
	
	if(isset($lastResponse))
	{
		$diff = $today->diff($dateCreated);
	}
	else
	{
		$diff = $today->diff($dateNotCreated);
	}
}
echo 240 / 23;

Expected result:
----------------
Not NAN

Actual result:
--------------
NAN