diff --git a/edi_core_oca/models/edi_backend.py b/edi_core_oca/models/edi_backend.py
index dfeefbdeb..9b94da8f4 100644
--- a/edi_core_oca/models/edi_backend.py
+++ b/edi_core_oca/models/edi_backend.py
@@ -295,12 +295,20 @@ def exchange_send(self, exchange_record):
         return res
 
     def _swallable_exceptions(self):
-        # TODO: improve this list
+        # These errors are permanent because retrying the same data will fail again.
+        # They should be swallowed so the exchange can move to an error state.
+        #
+        # OperationalError is excluded because it may be transient and should be
+        # re-raised to allow retries.
         return (
             ValueError,
             FileNotFoundError,
             exceptions.UserError,
             exceptions.ValidationError,
+            IntegrityError,
+            TypeError,
+            LookupError,  # covers KeyError / IndexError
+            AttributeError,
         )
 
     def _send_retryable_exceptions(self):
diff --git a/edi_core_oca/tests/test_backend_process.py b/edi_core_oca/tests/test_backend_process.py
index de259115e..dda6af90e 100644
--- a/edi_core_oca/tests/test_backend_process.py
+++ b/edi_core_oca/tests/test_backend_process.py
@@ -105,12 +105,28 @@ def test_process_outbound_record(self):
             record.action_exchange_process()
 
     def test_process_record_with_integrity_error(self):
+        # IntegrityError is permanent (e.g. a DB unique constraint
+        # violation): retrying the same data would fail again, so it must
+        # be swallowed and move the record to an error state instead of
+        # being re-raised and leaving it stuck in "input_received".
         self.record.write({"edi_exchange_state": "input_received"})
-        with self.assertRaises(IntegrityError):
-            self.backend.with_context(
-                test_break_process=IntegrityError("SQL error")
-            ).exchange_process(self.record)
-        self.assertRecordValues(self.record, [{"edi_exchange_state": "input_received"}])
-        self.assertFalse(self.record.exchange_error)
+        with self.assertRaisesRegex(IntegrityError, "SQL error"):
+            self.record.with_context(
+                test_break_process=IntegrityError("SQL error"),
+                _edi_process_break_on_error=True,
+            ).action_exchange_process()
+
+        self.record.with_context(
+            test_break_process=IntegrityError("SQL error")
+        ).action_exchange_process()
+        self.assertRecordValues(
+            self.record,
+            [
+                {
+                    "edi_exchange_state": "input_processed_error",
+                    "exchange_error": "SQL error",
+                }
+            ],
+        )
 
     # TODO: test ack file are processed