if ! empty $groupvariable not working

Hey guys!

I've got the same issue I had a few months ago. I'm not sure we ever really fixed it.

Querying if a group is empty or not doesn't seem to work as described in the docs.

The code I'm using:

// Coverage Shortcode

	function epi_publication_coverage_shortcode() {

		ob_start();

		// Press Coverage

				$coveragegroup = rwmb_meta( 'epi_pubcoverage' );

				if ( ! empty( $coveragegroup ) ) {

					echo 'NOT EMPTY';

				}

				else {

				}

		return ob_get_clean();

	}

	add_shortcode('show_publication_coverage','epi_publication_coverage_shortcode');

Displays "NOT EMPTY" on all posts, even if they don't have any coverage.

Is the group saving a blank field somewhere? Should I be querying on a checkbox or something instead?

Code used to register group:

// Add Coverage Meta Boxes

	$meta_boxes[] = array(
			'title'      => 'Press Coverage',
			'post_types' => array('post', 'report', 'analysis', 'guest-blog'),
			'context'    => 'normal',
			'priority'   => 'low',
			'desc'       => '(drag to reorder)',
			'fields' 	 => array(
					array(
							'id'         => 'epi_pubcoverage',
							'type'       => 'group',
							'clone'      => true,
							'sort_clone' => true,
							'fields'     => array(
									array(
											'name'  => 'Title',
											'id'    => $prefix . 'pubcoveragedesc',
											'type'  => 'text',
											'desc'  => 'Title or description for link',
									),
									array(
											'name'  => 'URL',
											'id'    => $prefix . 'pubcoverageurl',
											'type'  => 'text',
											'desc'  => 'Link to coverage',
									),
									array(
											'name'  => 'Date',
											'id'    => $prefix . 'pubcoveragedate',
											'type'  => 'date',
											'desc'  => 'Date of event coverage',
									),
							),
					),
			),
	);

return $meta_boxes;

And all plugins have been updated to latest versions.