diff --git a/src/Model/Contact.php b/src/Model/Contact.php
index c46b15b943..04cece5359 100644
--- a/src/Model/Contact.php
+++ b/src/Model/Contact.php
@@ -843,6 +843,7 @@ class Contact
 			// create an unfollow slap
 			$item = [];
 			$item['verb'] = Activity::O_UNFOLLOW;
+			$item['gravity'] = GRAVITY_ACTIVITY;
 			$item['follow'] = $contact["url"];
 			$item['body'] = '';
 			$item['title'] = '';
@@ -2470,6 +2471,7 @@ class Contact
 				// create a follow slap
 				$item = [];
 				$item['verb'] = Activity::FOLLOW;
+				$item['gravity'] = GRAVITY_ACTIVITY;
 				$item['follow'] = $contact["url"];
 				$item['body'] = '';
 				$item['title'] = '';
diff --git a/src/Protocol/ActivityPub/Processor.php b/src/Protocol/ActivityPub/Processor.php
index 02ea24224a..43aebce64f 100644
--- a/src/Protocol/ActivityPub/Processor.php
+++ b/src/Protocol/ActivityPub/Processor.php
@@ -989,7 +989,7 @@ class Processor
 		$parent_author = Contact::getDetailsByURL($parent['author-link'], 0);
 
 		$implicit_mentions = [];
-		if (empty($parent_author)) {
+		if (empty($parent_author['url'])) {
 			Logger::notice('Author public contact unknown.', ['author-link' => $parent['author-link'], 'item-id' => $parent['id']]);
 		} else {
 			$implicit_mentions[] = $parent_author['url'];
@@ -1003,7 +1003,7 @@ class Processor
 
 		foreach ($parent_terms as $term) {
 			$contact = Contact::getDetailsByURL($term['url'], 0);
-			if (!empty($contact)) {
+			if (!empty($contact['url'])) {
 				$implicit_mentions[] = $contact['url'];
 				$implicit_mentions[] = $contact['nurl'];
 				$implicit_mentions[] = $contact['alias'];