diff --git a/app/celery/tasks.py b/app/celery/tasks.py
index d7f3d7a15..f9c68d874 100644
--- a/app/celery/tasks.py
+++ b/app/celery/tasks.py
@@ -420,22 +420,23 @@ def update_letter_notifications_statuses(self, filename):
             update_letter_notification(filename, temporary_failures, update)
             sorted_letter_counts[update.cost_threshold] += 1
 
-        if temporary_failures:
-            # This will alert Notify that DVLA was unable to deliver the letters, we need to investigate
-            message = "DVLA response file: {filename} has failed letters with notification.reference {failures}".format(
-                filename=filename, failures=temporary_failures)
-            raise DVLAException(message)
+        try:
+            if sorted_letter_counts.keys() - {'Unsorted', 'Sorted'}:
+                unknown_status = sorted_letter_counts.keys() - {'Unsorted', 'Sorted'}
 
-        if sorted_letter_counts.keys() - {'Unsorted', 'Sorted'}:
-            unknown_status = sorted_letter_counts.keys() - {'Unsorted', 'Sorted'}
+                message = 'DVLA response file: {} contains unknown Sorted status {}'.format(
+                    filename, unknown_status
+                )
+                raise DVLAException(message)
 
-            message = 'DVLA response file: {} contains unknown Sorted status {}'.format(
-                filename, unknown_status
-            )
-            raise DVLAException(message)
-
-        billing_date = get_billing_date_in_bst_from_filename(filename)
-        persist_daily_sorted_letter_counts(billing_date, sorted_letter_counts)
+            billing_date = get_billing_date_in_bst_from_filename(filename)
+            persist_daily_sorted_letter_counts(billing_date, sorted_letter_counts)
+        finally:
+            if temporary_failures:
+                # This will alert Notify that DVLA was unable to deliver the letters, we need to investigate
+                message = "DVLA response file: {filename} has failed letters with notification.reference {failures}" \
+                    .format(filename=filename, failures=temporary_failures)
+                raise DVLAException(message)
 
 
 def get_billing_date_in_bst_from_filename(filename):
diff --git a/tests/app/celery/test_ftp_update_tasks.py b/tests/app/celery/test_ftp_update_tasks.py
index 435ccab93..5dc714046 100644
--- a/tests/app/celery/test_ftp_update_tasks.py
+++ b/tests/app/celery/test_ftp_update_tasks.py
@@ -113,6 +113,25 @@ def test_update_letter_notifications_statuses_raises_error_for_unknown_sorted_st
     ) in str(e)
 
 
+def test_update_letter_notifications_statuses_still_raises_temp_failure_error_with_unknown_sorted_status(
+    notify_api,
+    mocker,
+    sample_letter_template
+):
+    valid_file = 'ref-foo|Failed|1|unknown'
+    mocker.patch('app.celery.tasks.s3.get_s3_file', return_value=valid_file)
+    create_notification(sample_letter_template, reference='ref-foo', status=NOTIFICATION_SENDING,
+                        billable_units=0)
+
+    with pytest.raises(DVLAException) as e:
+        update_letter_notifications_statuses(filename="failed.txt")
+
+    failed = ["ref-foo"]
+    assert "DVLA response file: {filename} has failed letters with notification.reference {failures}".format(
+        filename="failed.txt", failures=failed
+    ) in str(e)
+
+
 def test_update_letter_notifications_statuses_calls_with_correct_bucket_location(notify_api, mocker):
     s3_mock = mocker.patch('app.celery.tasks.s3.get_s3_object')