Why does the assignment of a constant to the field that will be displayed in the email template not work in the form.result.new component?

Question

1C-Bitrix

this is in init
$get_domain = explode('.', $_SERVER["HTTP_HOST"]);
define("GET_DOMAIN", $get_domain[1] );
it's in form.result.new file components
$arResult["arAnswers"]["TEST"][0]["VALUE"]= "TEST!!!";
if ( GET_DOMAIN ) {
$arResult["arAnswers"]["DOMAIN"][0]["VALUE"] = GET_DOMAIN;}

Answer 1

It's unclear.
Is it possible that the letter is sent via CEvent::Send and conditionally in the background (not on this hit\crown), and the change is made in the component template after it has been sent to the event table?

Answer 2

define("GET_DOMAIN", $get_domain[1] );

Because you are assigning a non-scalar value. Use global instead of constant.