Publishpress metadata conflict

The Publishpress plugin causes an error in the administration screen of Grid Gallery Items of the Abcfolio responsive grid gallery plugins custom pro, a message like this comes out and does not allow to see the items added in the gallery:

Warning: stripos () expects parameter 1 to be string, array given in /home/web/public_html/wp-content/plugins/publishpress/modules/editorial-metadata/editorial-metadata.php on line 850

Warning: strtolower () expects parameter 1 to be string, array given in /home/web/public_html/wp-includes/formatting.php on line 1902

If Publishpress metadata is disabled, that error disappears.