diff --git a/app/models/post_timing.rb b/app/models/post_timing.rb
index 44d683db50d..6bfc5b7f2bd 100644
--- a/app/models/post_timing.rb
+++ b/app/models/post_timing.rb
@@ -148,6 +148,16 @@ class PostTiming < ActiveRecord::Base
   MAX_READ_TIME_PER_BATCH = 60 * 1000.0
 
   def self.process_timings(current_user, topic_id, topic_time, timings, opts = {})
+    lookup_column = current_user.whisperer? ? "highest_staff_post_number" : "highest_post_number"
+    highest_post_number = DB.query_single(<<~SQL, topic_id: topic_id).first
+          SELECT #{lookup_column}
+          FROM topics
+          WHERE id = :topic_id
+        SQL
+
+    # does not exist log nothing
+    return if highest_post_number.nil?
+
     UserStat.update_time_read!(current_user.id)
 
     max_time_per_post = ((Time.now - current_user.created_at) * 1000.0)
@@ -163,6 +173,7 @@ class PostTiming < ActiveRecord::Base
       i -= 1
       timings[i][1] = max_time_per_post if timings[i][1] > max_time_per_post
       timings.delete_at(i) if timings[i][0] < 1
+      timings.delete_at(i) if timings[i][0] > highest_post_number
     end
 
     timings.each_with_index do |(post_number, time), index|
diff --git a/app/models/topic_user.rb b/app/models/topic_user.rb
index e8c15fd6d51..cc9ce74b5c5 100644
--- a/app/models/topic_user.rb
+++ b/app/models/topic_user.rb
@@ -308,7 +308,14 @@ class TopicUser < ActiveRecord::Base
     UPDATE_TOPIC_USER_SQL = <<~SQL
       UPDATE topic_users
       SET
-        last_read_post_number = GREATEST(:post_number, tu.last_read_post_number),
+        last_read_post_number =
+          LEAST(
+            CASE WHEN :whisperer
+              THEN highest_staff_post_number
+              ELSE highest_post_number END
+            ,
+            GREATEST(:post_number, tu.last_read_post_number)
+          ),
         total_msecs_viewed = LEAST(tu.total_msecs_viewed + :msecs,86400000),
         notification_level =
            case when tu.notifications_reason_id is null and (tu.total_msecs_viewed + :msecs) >
@@ -357,6 +364,7 @@ class TopicUser < ActiveRecord::Base
         msecs: msecs,
         tracking: notification_levels[:tracking],
         threshold: SiteSetting.default_other_auto_track_topics_after_msecs,
+        whisperer: user.whisperer?,
       }
 
       rows = DB.query(UPDATE_TOPIC_USER_SQL, args)
diff --git a/spec/models/post_timing_spec.rb b/spec/models/post_timing_spec.rb
index eb39cc40c0e..341e7385f59 100644
--- a/spec/models/post_timing_spec.rb
+++ b/spec/models/post_timing_spec.rb
@@ -83,6 +83,7 @@ RSpec.describe PostTiming do
 
       (2..5).each { |i| Fabricate(:post, topic: post.topic, post_number: i) }
       user2 = Fabricate(:coding_horror, created_at: 1.day.ago)
+      Topic.reset_highest(post.topic.id)
 
       PostActionCreator.like(user2, post)
 
diff --git a/spec/models/topic_user_spec.rb b/spec/models/topic_user_spec.rb
index 5e027aa3284..6954c17964c 100644
--- a/spec/models/topic_user_spec.rb
+++ b/spec/models/topic_user_spec.rb
@@ -228,6 +228,12 @@ RSpec.describe TopicUser do
         today = Time.zone.now
         freeze_time Time.zone.now
 
+        # ensure data model is correct for the test
+        # logging an update to a row that does not exist
+        # is not supported
+        _post1 = Fabricate(:post, topic: topic)
+        _post2 = Fabricate(:post, topic: topic)
+
         TopicUser.update_last_read(user, topic.id, 1, 1, 0)
 
         tomorrow = 1.day.from_now
diff --git a/spec/requests/topics_controller_spec.rb b/spec/requests/topics_controller_spec.rb
index 9463d33151b..27e92128b73 100644
--- a/spec/requests/topics_controller_spec.rb
+++ b/spec/requests/topics_controller_spec.rb
@@ -4626,6 +4626,62 @@ RSpec.describe TopicsController do
   describe "#timings" do
     fab!(:post_1) { Fabricate(:post, user: post_author1, topic: topic) }
 
+    before do
+      # admins
+      SiteSetting.whispers_allowed_groups = "1"
+    end
+
+    let(:whisper) do
+      Fabricate(:post, user: post_author1, topic: topic, post_type: Post.types[:whisper])
+    end
+
+    it "should gracefully handle invalid timings sent in" do
+      sign_in(user)
+      params = {
+        topic_id: topic.id,
+        topic_time: 5,
+        timings: {
+          post_1.post_number => 2,
+          whisper.post_number => 2,
+          1000 => 100,
+        },
+      }
+
+      post "/topics/timings.json", params: params
+      expect(response.status).to eq(200)
+
+      tu = TopicUser.find_by(user: user, topic: topic)
+      expect(tu.last_read_post_number).to eq(post_1.post_number)
+
+      # lets also test timing recovery here
+      tu.update!(last_read_post_number: 999)
+
+      post "/topics/timings.json", params: params
+
+      tu = TopicUser.find_by(user: user, topic: topic)
+      expect(tu.last_read_post_number).to eq(post_1.post_number)
+    end
+
+    it "should gracefully handle invalid timings sent in from staff" do
+      sign_in(admin)
+
+      post "/topics/timings.json",
+           params: {
+             topic_id: topic.id,
+             topic_time: 5,
+             timings: {
+               post_1.post_number => 2,
+               whisper.post_number => 2,
+               1000 => 100,
+             },
+           }
+
+      expect(response.status).to eq(200)
+
+      tu = TopicUser.find_by(user: admin, topic: topic)
+      expect(tu.last_read_post_number).to eq(whisper.post_number)
+    end
+
     it "should record the timing" do
       sign_in(user)
 
@@ -5382,7 +5438,7 @@ RSpec.describe TopicsController do
 
       it "resets bump correctly" do
         post1 = Fabricate(:post, user: post_author1, topic: topic, created_at: 2.days.ago)
-        post2 = Fabricate(:post, user: post_author1, topic: topic, created_at: 1.day.ago)
+        _post2 = Fabricate(:post, user: post_author1, topic: topic, created_at: 1.day.ago)
 
         put "/t/#{topic.id}/reset-bump-date/#{post1.id}.json"
         expect(response.status).to eq(200)