diff --git a/app/models/card/exportable.rb b/app/models/card/exportable.rb
index ffff82581..b147c47d9 100644
--- a/app/models/card/exportable.rb
+++ b/app/models/card/exportable.rb
@@ -67,7 +67,7 @@ module Card::Exportable
     end
 
     def collect_attachments
-      attachments.to_a + comments.flat_map { |c| c.attachments.to_a }
+      (attachments.to_a + comments.flat_map { |c| c.attachments.to_a }).uniq(&:blob_id)
     end
 
     def export_status