When writing event handlers, manipulate elements relative to the element was clicked to avoid unintended concequences.

reusable.js

$('._ak-subscribe-close').on('click', function(){
    $('._ak-email_subscribe').removeClass('_ak-email_subscribe--opened');
});

//becomes

$('._ak-subscribe-close').on('click', function(e){
	var $wrapper = $(e.currentTarget).closest('._ak-email_subscribe')
	$wrapper.removeClass('_ak-email_subscribe--opened');
});