PHP Error on Grid Pages

Brilliant Plugin!!
Just recently I’ve had some php errors showing on grid pages.

Notice: Undefined index: authors in /home/sites/public_html/mysite/wp-content/plugins/grid-plus/shortcodes/grid-templates/grid-posts.php on line 84
AND also on line 86

So on the grid-posts.php I have omitted the two lines and errors disappear.
Is there somehow to correct this rather than a workaround? Thanks.

//$authors = $grid_data_source['authors'];
$include_ids = isset($grid_data_source['include_ids']) ? $grid_data_source['include_ids'] : '';
//$exclude_ids = $grid_data_source['exclude_ids'];