Merge pull request #397 from nextcloud/backport/394/stable20

[stable20] Fixed the case when multiple announcements are added for the same gro…

lib/BackgroundJob.php

@@ -123,6 +123,7 @@ protected function createPublicity(Announcement $announcement, array $publicity)
 		if (\in_array('everyone', $groups, true)) {
 			$this->createPublicityEveryone($announcement->getUser(), $event, $notification, $publicity);
 		} else {
+			$this->notifiedUsers = [];
 			$this->createPublicityGroups($announcement->getUser(), $event, $notification, $groups, $publicity);
 		}
 	}