diff --git a/app/models/topic_tracking_state.rb b/app/models/topic_tracking_state.rb
index 05334ccad..0bf3fa709 100644
--- a/app/models/topic_tracking_state.rb
+++ b/app/models/topic_tracking_state.rb
@@ -148,14 +148,15 @@ class TopicTrackingState
           ((#{unread}) OR (#{new})) AND
           (topics.visible OR u.admin OR u.moderator) AND
           topics.deleted_at IS NULL AND
-          ( category_id IS NULL OR NOT c.read_restricted OR category_id IN (
+          ( category_id IS NULL OR NOT c.read_restricted OR u.admin OR category_id IN (
               SELECT c2.id FROM categories c2
               JOIN category_groups cg ON cg.category_id = c2.id
               JOIN group_users gu ON gu.user_id = u.id AND cg.group_id = gu.group_id
               WHERE c2.read_restricted )
           )
           AND NOT EXISTS( SELECT 1 FROM category_users cu
-                          WHERE cu.user_id = u.id AND
+                          WHERE last_read_post_number IS NULL AND
+                               cu.user_id = u.id AND
                                cu.category_id = topics.category_id AND
                                cu.notification_level = #{CategoryUser.notification_levels[:muted]})
 
diff --git a/spec/models/topic_tracking_state_spec.rb b/spec/models/topic_tracking_state_spec.rb
index 3c94c26b1..6897a2550 100644
--- a/spec/models/topic_tracking_state_spec.rb
+++ b/spec/models/topic_tracking_state_spec.rb
@@ -15,11 +15,34 @@ describe TopicTrackingState do
     TopicTrackingState.publish_unread(post)
   end
 
+  it "correctly handles muted categories" do
+
+    user = Fabricate(:user)
+    post
+
+    report = TopicTrackingState.report([user.id])
+    expect(report.length).to eq(1)
+
+    CategoryUser.create!(user_id: user.id,
+                         notification_level: CategoryUser.notification_levels[:muted],
+                         category_id: post.topic.category_id
+                         )
+
+    create_post(topic_id: post.topic_id)
+
+    report = TopicTrackingState.report([user.id])
+    expect(report.length).to eq(0)
+
+    TopicUser.create!(user_id: user.id, topic_id: post.topic_id, last_read_post_number: 1, notification_level: 3)
+
+    report = TopicTrackingState.report([user.id])
+    expect(report.length).to eq(1)
+  end
+
   it "correctly gets the tracking state" do
     report = TopicTrackingState.report([user.id])
     expect(report.length).to eq(0)
 
-    new_post = post
     post.topic.notifier.watch_topic!(post.topic.user_id)
 
     report = TopicTrackingState.report([user.id])