diff --git a/app/models/protocol.rb b/app/models/protocol.rb
index d9028033f..5e3fa855b 100644
--- a/app/models/protocol.rb
+++ b/app/models/protocol.rb
@@ -581,7 +581,7 @@ class Protocol < ApplicationRecord
   end
 
   def set_linked_at
-    linked_at = created_at
+    self.linked_at = created_at
     self.save!
   end