diff --git a/odoo/addons/test_read_group/tests/test_date_range.py b/odoo/addons/test_read_group/tests/test_date_range.py
index 3b0d85e743e..0071c4146ac 100644
--- a/odoo/addons/test_read_group/tests/test_date_range.py
+++ b/odoo/addons/test_read_group/tests/test_date_range.py
@@ -112,3 +112,17 @@ class TestDateRange(common.TransactionCase):
 
         groups = self.Model.read_group([], fields=['date', 'value'], groupby=['date:quarter', 'date:day'], lazy=False)
         self.assertEqual(groups, expected)
+
+    def test_duplicate_month(self):
+        records = self.Model.create([
+            {'date': '2022-01-29', 'value': 1}])
+        expected = [{
+            '__domain': ['&', '&', ('id', 'in', records.ids), '&', ('date', '>=', '2022-01-01'), ('date', '<', '2022-02-01'), ('date', '=', 'January 2022')],
+            '__count': 1,
+            '__range': {'date:month': {'from': '2022-01-01', 'to': '2022-02-01'}},
+            'value': 1,
+            'date:month': 'January 2022'
+        }]
+        groups = self.Model.read_group(
+            [('id', 'in', records.ids)], fields=['date', 'value'], groupby=['date:month', 'date:month'], lazy=False)
+        self.assertEqual(groups, expected)
diff --git a/odoo/models.py b/odoo/models.py
index 4627fd60da1..b96a8a17a84 100644
--- a/odoo/models.py
+++ b/odoo/models.py
@@ -2455,7 +2455,7 @@ class BaseModel(metaclass=MetaModel):
                 additional_domain = [(field_name, '=', value)]
 
                 if field.type in ('date', 'datetime'):
-                    if value:
+                    if value and isinstance(value, (datetime.date, datetime.datetime)):
                         range_start = value
                         range_end = value + interval
                         if field.type == 'datetime':
@@ -2485,7 +2485,7 @@ class BaseModel(metaclass=MetaModel):
                                 (field_name, '>=', range_start),
                                 (field_name, '<', range_end),
                         ]
-                    else:
+                    elif not value:
                         # Set the __range of the group containing records with an unset
                         # date/datetime field value to False.
                         row.setdefault('__range', {})[group] = False