diff --git a/lib/post_revisor.rb b/lib/post_revisor.rb
index 2ba445324cc..7264fe24286 100644
--- a/lib/post_revisor.rb
+++ b/lib/post_revisor.rb
@@ -527,7 +527,7 @@ class PostRevisor
     modifications = post_changes.merge(@topic_changes.diff)
     if modifications.keys.size == 1 && tags_diff = modifications["tags"]
       a, b = tags_diff[0] || [], tags_diff[1] || []
-      changed_tags = (a + b) - (a & b)
+      changed_tags = ((a + b) - (a & b)).map(&:presence).compact
       if (changed_tags - DiscourseTagging.hidden_tag_names(nil)).empty?
         return true
       end
diff --git a/spec/components/post_revisor_spec.rb b/spec/components/post_revisor_spec.rb
index 95bd120208b..ed4f2887e7f 100644
--- a/spec/components/post_revisor_spec.rb
+++ b/spec/components/post_revisor_spec.rb
@@ -762,6 +762,14 @@ describe PostRevisor do
               }.to_not change { topic.reload.bumped_at }
             end
 
+            it "doesn't bump topic if empty string is given" do
+              topic.tags = Tag.where(name: ['important', 'secret']).to_a
+              expect {
+                result = subject.revise!(Fabricate(:admin), raw: post.raw, tags: [""])
+                expect(result).to eq(true)
+              }.to_not change { topic.reload.bumped_at }
+            end
+
             it "creates a hidden revision" do
               subject.revise!(Fabricate(:admin), raw: post.raw, tags: topic.tags.map(&:name) + ['secret'])
               expect(post.reload.revisions.first.hidden).to eq(true)