Now without array_merge

src/Model/Item.php

@@ -1354,7 +1354,7 @@ class Item extends BaseObject
 		 * We have to check several networks since Friendica posts could be repeated
 		 * via OStatus (maybe Diasporsa as well)
 		 */
-		if (in_array($item['network'], array_merge(Protocol::FEDERATED ,['']))) {
+		if (empty($item['network']) || in_array($item['network'], Protocol::FEDERATED)) {
 			$condition = ["`uri` = ? AND `uid` = ? AND `network` IN (?, ?, ?)",
 				trim($item['uri']), $item['uid'],
 				Protocol::DIASPORA, Protocol::DFRN, Protocol::OSTATUS];