diff --git a/lib/ansible/plugins/callback/__init__.py b/lib/ansible/plugins/callback/__init__.py
index 6b41e1dd9c..436e963e04 100644
--- a/lib/ansible/plugins/callback/__init__.py
+++ b/lib/ansible/plugins/callback/__init__.py
@@ -236,9 +236,7 @@ class CallbackBase(AnsiblePlugin):
     def _clean_results(self, result, task_name):
         ''' removes data from results for display '''
         if task_name in ['debug']:
-            for remove_key in ('invocation'):
-                if remove_key in result:
-                    del result[remove_key]
+            result.pop('invocation', None)
 
     def set_play_context(self, play_context):
         pass
diff --git a/test/units/plugins/callback/test_callback.py b/test/units/plugins/callback/test_callback.py
index 0e230472fa..9ccf868753 100644
--- a/test/units/plugins/callback/test_callback.py
+++ b/test/units/plugins/callback/test_callback.py
@@ -67,15 +67,53 @@ class TestCallbackResults(unittest.TestCase):
         res = cb._get_item(results)
         self.assertEquals(res, "some_item")
 
+    def test_clean_results_debug_task(self):
+        cb = CallbackBase()
+        result = {'item': 'some_item',
+                  'invocation': 'foo --bar whatever [some_json]',
+                  'a': 'a single a in result note letter a is in invocation',
+                  'b': 'a single b in result note letter b is not in invocation',
+                  'changed': True}
+
+        cb._clean_results(result, 'debug')
+
+        # See https://github.com/ansible/ansible/issues/33723
+        self.assertTrue('a' in result)
+        self.assertTrue('b' in result)
+        self.assertFalse('invocation' in result)
+        self.assertTrue('changed' in result)
+
+    def test_clean_results_debug_task_no_invocation(self):
+        cb = CallbackBase()
+        result = {'item': 'some_item',
+                  'a': 'a single a in result note letter a is in invocation',
+                  'b': 'a single b in result note letter b is not in invocation',
+                  'changed': True}
+
+        cb._clean_results(result, 'debug')
+        self.assertTrue('a' in result)
+        self.assertTrue('b' in result)
+        self.assertTrue('changed' in result)
+        self.assertFalse('invocation' in result)
+
+    def test_clean_results_debug_task_empty_results(self):
+        cb = CallbackBase()
+        result = {}
+        cb._clean_results(result, 'debug')
+        self.assertFalse('invocation' in result)
+        self.assertEqual(len(result), 0)
+
     def test_clean_results(self):
         cb = CallbackBase()
         result = {'item': 'some_item',
                   'invocation': 'foo --bar whatever [some_json]',
+                  'a': 'a single a in result note letter a is in invocation',
+                  'b': 'a single b in result note letter b is not in invocation',
                   'changed': True}
 
-        self.assertTrue('changed' in result)
-        self.assertTrue('invocation' in result)
-        cb._clean_results(result, 'debug')
+        expected_result = result.copy()
+        cb._clean_results(result, 'ebug')
+        self.assertEqual(result, expected_result)
 
 
 class TestCallbackDumpResults(unittest.TestCase):