diff --git a/app/models/topic.rb b/app/models/topic.rb
index e5787076900..2dd51661d25 100644
--- a/app/models/topic.rb
+++ b/app/models/topic.rb
@@ -216,7 +216,8 @@ class Topic < ActiveRecord::Base
   end
 
   def inherit_auto_close_from_category
-    if !@ignore_category_auto_close &&
+    if !self.closed &&
+       !@ignore_category_auto_close &&
        self.category &&
        self.category.auto_close_hours &&
        !public_topic_timer&.execute_at
@@ -1010,7 +1011,7 @@ SQL
     topic_timer.status_type = status_type
 
     if time.blank?
-      topic_timer.trash!(trashed_by: by_user || Discourse.system_user)
+      topic_timer.trash!(by_user || Discourse.system_user)
       return
     end
 
diff --git a/spec/models/topic_spec.rb b/spec/models/topic_spec.rb
index a1d5334fce6..6dbcbdd340a 100644
--- a/spec/models/topic_spec.rb
+++ b/spec/models/topic_spec.rb
@@ -1066,6 +1066,21 @@ describe Topic do
             expect(topic_timer.execute_at).to be_within(1.second).of(Time.zone.now + 5.hours)
           end
 
+          describe 'when topic is already closed' do
+            before do
+              SiteSetting.queue_jobs = true
+              topic.update_status('closed', true, Discourse.system_user)
+            end
+
+            it 'should not set a topic timer' do
+              expect { topic.change_category_to_id(new_category.id) }
+                .to change { TopicTimer.with_deleted.count }.by(0)
+
+              expect(topic.closed).to eq(true)
+              expect(topic.reload.category).to eq(new_category)
+            end
+          end
+
           describe 'when topic has an existing topic timer' do
             let(:topic_timer) { Fabricate(:topic_timer, topic: topic) }