diff --git a/odoo/addons/test_new_api/tests/test_properties.py b/odoo/addons/test_new_api/tests/test_properties.py
index d6bd240abee..2574f82cba8 100644
--- a/odoo/addons/test_new_api/tests/test_properties.py
+++ b/odoo/addons/test_new_api/tests/test_properties.py
@@ -1186,6 +1186,28 @@ class PropertiesCase(TransactionCase):
             message.attributes,
             [{'name': 'new_property', 'type': 'char', 'value': 'test value'}])
 
+        # re-write the same parent again and check that value are not reset
+        message.discussion = message.discussion
+        self.assertEqual(
+            message.attributes,
+            [{'name': 'new_property', 'type': 'char', 'value': 'test value'}])
+
+        # trigger a other onchange after setting the properties
+        # and check that it does not impact the properties
+        message.discussion.attributes_definition = []
+        message_form = Form(message)
+        message.attributes = [{
+            'name': 'new_property',
+            'type': 'char',
+            'value': 'test value',
+            'definition_changed': True,
+        }]
+        message_form.body = "a" * 42
+        message = message_form.save()
+        self.assertEqual(
+            message.attributes,
+            [{'name': 'new_property', 'type': 'char', 'value': 'test value'}])
+
     @mute_logger('odoo.fields')
     def test_properties_field_definition_update(self):
         """Test the definition update from the child."""
diff --git a/odoo/models.py b/odoo/models.py
index a7d8567ed18..3eda64a9170 100644
--- a/odoo/models.py
+++ b/odoo/models.py
@@ -6827,9 +6827,26 @@ class BaseModel(metaclass=MetaModel):
                 for name, subnames in self['<tree>'].items():
                     if name == 'id':
                         continue
+                    field = record._fields[name]
+                    if (field.type == 'properties' and field.definition_record in field_name
+                       and other.get(name) == self[name] == []):
+                        # TODO: The parent field on "record" can be False, if it was changed,
+                        # (even if if was changed to a not Falsy value) because of
+                        # >>> initial_values = dict(values, **dict.fromkeys(names, False))
+                        # If it's the case when we will read the properties field on this record,
+                        # it will return False as well (no parent == no definition)
+                        # So record at the following line, will always return a empty properties
+                        # because the definition record is always False if it triggered the onchange
+                        # >>> snapshot0 = Snapshot(record, nametree, fetch=(not first_call))
+                        # but we need "snapshot0" to have the old value to be able
+                        # to compare it with the new one and trigger the onchange if necessary.
+                        # In that particular case, "other.get(name)" must contains the
+                        # non empty properties value.
+                        result[name] = []
+                        continue
+
                     if not force and other.get(name) == self[name]:
                         continue
-                    field = record._fields[name]
                     if field.type not in ('one2many', 'many2many'):
                         result[name] = field.convert_to_onchange(self[name], record, {})
                     else:
@@ -6957,18 +6974,6 @@ class BaseModel(metaclass=MetaModel):
         # make a snapshot based on the initial values of record
         snapshot0 = Snapshot(record, nametree, fetch=(not first_call))
 
-        for name in initial_values:
-            # TODO: The parent field on "record" can be False, if it was changed,
-            # (even if if was changed to a not Falsy value) because of
-            # >>> initial_values = dict(values, **dict.fromkeys(names, False))
-            # If it's the case when we will read the properties field on this record,
-            # it will return False as well (no parent == no definition) but we need
-            # "snapshot0" to have the old value to be able to compare it with the new one
-            # and trigger the onchange if necessary.
-            field = self._fields.get(name)
-            if field and field.type == 'properties':
-                snapshot0[name] = initial_values[name]
-
         # store changed values in cache; also trigger recomputations based on
         # subfields (e.g., line.a has been modified, line.b is computed stored
         # and depends on line.a, but line.b is not in the form view)