This is an old thread, but I used Josue’s code to insert the sharing buttons at the end of a page with template builder content and found out that a closing div tag is missing.
Just in case somebody else runs into this, the correct code would be:

add_action('ava_after_content', 'avia_add_social_toolbars', 10, 2);
function avia_add_social_toolbars($id = "", $context = "")
{
	if($context == "page" || $context == "single-portfolio" || $context == "product")
	avia_social_share_links();

}

add_filter('avf_template_builder_content', 'avia_add_social_toolbar_template_builder', 10, 1);
function avia_add_social_toolbar_template_builder($content = "")
{
	$content .= '<div id="custom_share_box" class="avia-section main_color container_wrap"><div class="container">';
	$content .= avia_social_share_links(array(), '', '', false);
	$content .= '</div></div>';
	return $content;
}

Thanks for the great support & documentation! :)