diff --git a/app/models/spree/order_decorator.rb b/app/models/spree/order_decorator.rb
index fec601be76..a723ce1198 100644
--- a/app/models/spree/order_decorator.rb
+++ b/app/models/spree/order_decorator.rb
@@ -166,7 +166,21 @@ Spree::Order.class_eval do
     shipments.each do |shipment|
       next if shipment.shipped?
       update_adjustment! shipment.adjustment if shipment.adjustment
-      shipment.save # updates included tax
+      begin
+        shipment.save # updates included tax
+      rescue ActiveRecord::RecordNotUnique => error
+        # This error was seen in production on `shipment.save` above.
+        # It caused lost payments and duplicate payments due to database rollbacks.
+        # While we don't understand the cause of this error yet, we rescue here
+        # because an outdated shipping fee is not as bad as a lost payment.
+        # And the shipping fee is already up-to-date when this error occurs.
+        # https://github.com/openfoodfoundation/openfoodnetwork/issues/3924
+        Bugsnag.notify(error) do |report|
+          report.add_tab(:order, attributes)
+          report.add_tab(:shipment, shipment.attributes)
+          report.add_tab(:shipment_in_db, Spree::Shipment.find_by_id(shipment.id).attributes)
+        end
+      end
     end
   end