diff --git a/odoo/addons/test_new_api/tests/test_new_fields.py b/odoo/addons/test_new_api/tests/test_new_fields.py
index b1b175a0435..04529592445 100644
--- a/odoo/addons/test_new_api/tests/test_new_fields.py
+++ b/odoo/addons/test_new_api/tests/test_new_fields.py
@@ -2125,6 +2125,34 @@ class TestFields(TransactionCaseWithUserDemo):
         moves = self.env['test_new_api.move'].search([('line_ids', 'in', line.id)])
         self.assertEqual(moves, move2)
 
+    def test_73_relational_inverse(self):
+        """ Check the consistency of relational fields with inverse(s). """
+        discussion1, discussion2 = self.env['test_new_api.discussion'].create([
+            {'name': "discussion1"}, {'name': "discussion2"},
+        ])
+        category1, category2 = self.env['test_new_api.category'].create([
+            {'name': "category1"}, {'name': "category2"},
+        ])
+
+        # assumption: category12 and category21 are in different order, but are
+        # in the same order when put in a set()
+        category12 = category1 + category2
+        category21 = category2 + category1
+        self.assertNotEqual(category12.ids, category21.ids)
+        self.assertEqual(list(set(category12.ids)), list(set(category21.ids)))
+
+        # make sure discussion1.categories is in cache; the write() below should
+        # update the cache of discussion1.categories by appending category12.ids
+        discussion1.categories
+        category12.write({'discussions': [Command.link(discussion1.id)]})
+        self.assertEqual(discussion1.categories.ids, category12.ids)
+
+        # make sure discussion2.categories is in cache; the write() below should
+        # update the cache of discussion2.categories by appending category21.ids
+        discussion2.categories
+        category21.write({'discussions': [Command.link(discussion2.id)]})
+        self.assertEqual(discussion2.categories.ids, category21.ids)
+
     def test_80_copy(self):
         Translations = self.env['ir.translation']
         discussion = self.env.ref('test_new_api.discussion_0')
diff --git a/odoo/fields.py b/odoo/fields.py
index 85eb6f94a1b..1f777e6c548 100644
--- a/odoo/fields.py
+++ b/odoo/fields.py
@@ -3882,7 +3882,7 @@ class Many2many(_RelationalMulti):
 
         # determine old and new relation {x: ys}
         set = OrderedSet
-        ids = {rid for recs, cs in records_commands_list for rid in recs.ids}
+        ids = set(rid for recs, cs in records_commands_list for rid in recs.ids)
         records = model.browse(ids)
 
         if self.store: