MB Blocks 1.8.0 stops enqueueing assets on frontend

Hello,

After the recent MB Block 1.8.0 update, the CSS file enqueued through enqueue_assets is not anymore loaded on the frontend. Downgrading back to MB Block 1.7.6 fixes it. Can you take a look? Here is my markup:

$meta_boxes[] = array(
		'id'              => 'twt-modules',
		'title'           => 'TWT Modules',
		'type'            => 'block',
		'icon'            => 'editor-table',
		'category'        => 'layout',
		'context'         => 'normal',
		'render_template' => get_stylesheet_directory() . '/blocks/twt-modules.php',
		'enqueue_assets' => function() {
			wp_enqueue_style('twt-modules', get_stylesheet_directory_uri().'/blocks/twt-modules.css', array(), filemtime(get_stylesheet_directory()."/blocks/twt-modules.css"));
		},
		'supports'        => array(
			'anchor'          => true,
			'customClassName' => true
		),
		'fields'          => array(
			array(
				'name'          => '',
				'id'            => 'modules',
				'type'          => 'group',
				'clone'         => true,
				'sort_clone'    => true,
				'collapsible'   => true,
				'default_state' => 'collapsed',
				'group_title'   => '{label}',
				'fields'        => array(
					array(
						'name' => 'Label',
						'id'   => 'label',
						'type' => 'text',
					),
					array(
						'name' => 'URL',
						'id'   => 'url',
						'type' => 'text',
					),
					array(
						'name' => 'Image',
						'id'   => 'img',
						'type' => 'single_image',
					)
				)
			)
		)
	);