diff --git a/src/database/mongo/sorted.js b/src/database/mongo/sorted.js
index 8ecbb1b129..21a1a6e61c 100644
--- a/src/database/mongo/sorted.js
+++ b/src/database/mongo/sorted.js
@@ -290,7 +290,10 @@ module.exports = function (db, module) {
 
 	module.sortedSetScores = function (key, values, callback) {
 		if (!key) {
-			return callback(null, null);
+			return setImmediate(callback, null, null);
+		}
+		if (!values.length) {
+			return setImmediate(callback, null, []);
 		}
 		values = values.map(helpers.valueToString);
 		db.collection('objects').find({ _key: key, value: { $in: values } }, { projection: { _id: 0, _key: 0 } }).toArray(function (err, result) {
diff --git a/src/database/postgres/sorted.js b/src/database/postgres/sorted.js
index 014bda1ba7..4b1dfa41c6 100644
--- a/src/database/postgres/sorted.js
+++ b/src/database/postgres/sorted.js
@@ -382,9 +382,11 @@ SELECT o."_key" k,
 
 	module.sortedSetScores = function (key, values, callback) {
 		if (!key) {
-			return callback(null, null);
+			return setImmediate(callback, null, null);
+		}
+		if (!values.length) {
+			return setImmediate(callback, null, []);
 		}
-
 		values = values.map(helpers.valueToString);
 
 		query({
diff --git a/src/database/redis/sorted.js b/src/database/redis/sorted.js
index 72a522c8eb..6dac8955aa 100644
--- a/src/database/redis/sorted.js
+++ b/src/database/redis/sorted.js
@@ -185,6 +185,9 @@ module.exports = function (redisClient, module) {
 	};
 
 	module.sortedSetScores = function (key, values, callback) {
+		if (!values.length) {
+			return setImmediate(callback, null, []);
+		}
 		helpers.execKeyValues(redisClient, 'batch', 'zscore', key, values, function (err, scores) {
 			if (err) {
 				return callback(err);
diff --git a/src/posts/bookmarks.js b/src/posts/bookmarks.js
index 241c5b85c3..c609408821 100644
--- a/src/posts/bookmarks.js
+++ b/src/posts/bookmarks.js
@@ -86,12 +86,7 @@ module.exports = function (Posts) {
 
 	Posts.hasBookmarked = function (pid, uid, callback) {
 		if (parseInt(uid, 10) <= 0) {
-			if (Array.isArray(pid)) {
-				callback(null, pid.map(() => false));
-			} else {
-				callback(null, false);
-			}
-			return;
+			return callback(null, Array.isArray(pid) ? pid.map(() => false) : false);
 		}
 
 		if (Array.isArray(pid)) {
diff --git a/src/topics/index.js b/src/topics/index.js
index 6828f8eae3..fb57fcd5d9 100644
--- a/src/topics/index.js
+++ b/src/topics/index.js
@@ -188,13 +188,15 @@ Topics.getTopicWithPosts = function (topicData, set, uid, start, stop, reverse,
 			topicData.bookmark = results.bookmark;
 			topicData.postSharing = results.postSharing;
 			topicData.deleter = results.deleter;
-			topicData.deletedTimestampISO = utils.toISOString(topicData.deletedTimestamp);
+			if (results.deleter) {
+				topicData.deletedTimestampISO = utils.toISOString(topicData.deletedTimestamp);
+			}
 			topicData.merger = results.merger;
-			topicData.mergedTimestampISO = utils.toISOString(topicData.mergedTimestamp);
+			if (results.merger) {
+				topicData.mergedTimestampISO = utils.toISOString(topicData.mergedTimestamp);
+			}
 			topicData.related = results.related || [];
-
 			topicData.unreplied = topicData.postcount === 1;
-
 			topicData.icons = [];
 
 			plugins.fireHook('filter:topic.get', { topic: topicData, uid: uid }, next);
@@ -245,14 +247,14 @@ function getMainPostAndReplies(topic, set, uid, start, stop, reverse, callback)
 }
 
 function getDeleter(topicData, callback) {
-	if (!topicData.deleterUid) {
+	if (!parseInt(topicData.deleterUid, 10)) {
 		return setImmediate(callback, null, null);
 	}
 	user.getUserFields(topicData.deleterUid, ['username', 'userslug', 'picture'], callback);
 }
 
 function getMerger(topicData, callback) {
-	if (!topicData.mergerUid) {
+	if (!parseInt(topicData.mergerUid, 10)) {
 		return setImmediate(callback, null, null);
 	}
 	async.waterfall([
diff --git a/src/topics/posts.js b/src/topics/posts.js
index 005e5d4eed..33dd80ef44 100644
--- a/src/topics/posts.js
+++ b/src/topics/posts.js
@@ -154,7 +154,7 @@ module.exports = function (Topics) {
 		if (!parentPids.length) {
 			return setImmediate(callback);
 		}
-
+		parentPids = _.uniq(parentPids);
 		var parentPosts;
 		async.waterfall([
 			async.apply(posts.getPostsFields, parentPids, ['uid']),
diff --git a/src/topics/tags.js b/src/topics/tags.js
index 4acc8810b5..2be85a2c73 100644
--- a/src/topics/tags.js
+++ b/src/topics/tags.js
@@ -232,13 +232,13 @@ module.exports = function (Topics) {
 	};
 
 	Topics.getTagData = function (tags, callback) {
-		var keys = tags.map(function (tag) {
-			return 'tag:' + tag.value;
-		});
+		if (!tags.length) {
+			return setImmediate(callback, null, []);
+		}
 
 		async.waterfall([
 			function (next) {
-				db.getObjects(keys, next);
+				db.getObjects(tags.map(tag => 'tag:' + tag.value), next);
 			},
 			function (tagData, next) {
 				tags.forEach(function (tag, index) {
diff --git a/test/database/sorted.js b/test/database/sorted.js
index f0320962cd..35adcdfd8a 100644
--- a/test/database/sorted.js
+++ b/test/database/sorted.js
@@ -581,6 +581,15 @@ describe('Sorted Set methods', function () {
 			});
 		});
 
+		it('should return empty array if values is an empty array', function (done) {
+			db.sortedSetScores('sortedSetTest1', [], function (err, scores) {
+				assert.ifError(err);
+				assert.equal(arguments.length, 2);
+				assert.deepStrictEqual(scores, []);
+				done();
+			});
+		});
+
 		it('should return scores properly', function (done) {
 			db.sortedSetsScore(['zeroScore', 'sortedSetTest1', 'doesnotexist'], 'value1', function (err, scores) {
 				assert.ifError(err);