What is the reason for the "Are you sure you want to do this" error?

Question

WordPress

Problem with Gravity Form plugin.
When you go to the "Confirmations", "Notifications" form settings tabs, an error appears "Are you sure you want to do this?"
At random, I found out that it is called by the code in the functions.php file of the active theme:

if ($ipad || $iphone || $android || $palmpre || $ipod || $berry || $mobile || $symb || $operam || $htc || $fennec || $winphone || $wp7 || $wp8 === true)  {
    $_POST['device'] = 'mobile'; 
}

else { 	$_POST['device']= 'pc'; }

specifically, passing strings to the POST array (there is a check for the device type, and then connecting the necessary styles / scripts, depending on the result).