diff --git a/app/controllers/user_avatars_controller.rb b/app/controllers/user_avatars_controller.rb
index 271cd412571..39050be70bd 100644
--- a/app/controllers/user_avatars_controller.rb
+++ b/app/controllers/user_avatars_controller.rb
@@ -173,7 +173,7 @@ class UserAvatarsController < ApplicationController
   def render_blank
     path = Rails.root + "public/images/avatar.png"
     expires_in 10.minutes, public: true
-    response.headers["Last-Modified"] = 10.minutes.ago.httpdate
+    response.headers["Last-Modified"] = Time.new('1990-01-01').httpdate
     response.headers["Content-Length"] = File.size(path).to_s
     send_file path, disposition: nil
   end
diff --git a/spec/requests/user_avatars_controller_spec.rb b/spec/requests/user_avatars_controller_spec.rb
index 73bbfe16cf0..5e8d0e79b09 100644
--- a/spec/requests/user_avatars_controller_spec.rb
+++ b/spec/requests/user_avatars_controller_spec.rb
@@ -107,7 +107,9 @@ describe UserAvatarsController do
       get "/user_avatar/default/xxx/51/777.png"
 
       expect(response.status).to eq(200)
-      expect(response.headers["Last-Modified"]).to eq(10.minutes.ago.httpdate)
+
+      # this image should be really old so when it is fixed various algorithms pick it up
+      expect(response.headers["Last-Modified"]).to eq(Time.new('1990-01-01').httpdate)
     end
 
     it 'serves image even if size missing and its in local mode' do