diff --git a/patroni/ha.py b/patroni/ha.py
index 3673e775..6ebbdd97 100644
--- a/patroni/ha.py
+++ b/patroni/ha.py
@@ -654,6 +654,14 @@ class Ha(object):
             current = CaseInsensitiveSet(sync.members)
             picked, allow_promote = self.state_handler.sync_handler.current_state(self.cluster)
 
+            if picked == current and current != allow_promote:
+                logger.warning('Inconsistent state between synchronous_standby_names = %s and /sync = %s key '
+                               'detected, updating synchronous replication key...', list(allow_promote), list(current))
+                sync = self.dcs.write_sync_state(self.state_handler.name, allow_promote, version=sync.version)
+                if not sync:
+                    return logger.warning("Updating sync state failed")
+                current = CaseInsensitiveSet(sync.members)
+
             if picked != current:
                 # update synchronous standby list in dcs temporarily to point to common nodes in current and picked
                 sync_common = current & allow_promote
diff --git a/tests/test_ha.py b/tests/test_ha.py
index 29c4ca11..7a7ca069 100644
--- a/tests/test_ha.py
+++ b/tests/test_ha.py
@@ -1313,6 +1313,24 @@ class TestHa(PostgresInit):
             self.ha.run_cycle()
             self.assertEqual(mock_logger.call_args[0][0], 'Updating sync state failed')
 
+    @patch.object(Cluster, 'is_unlocked', Mock(return_value=False))
+    def test_inconsistent_synchronous_state(self):
+        self.ha.is_synchronous_mode = true
+        self.ha.has_lock = true
+        self.p.name = 'leader'
+        self.ha.cluster = get_cluster_initialized_without_leader(sync=('leader', 'a'))
+        self.p.sync_handler.current_state = Mock(return_value=(CaseInsensitiveSet('a'), CaseInsensitiveSet()))
+        self.ha.dcs.write_sync_state = Mock(return_value=SyncState.empty())
+        mock_set_sync = self.p.sync_handler.set_synchronous_standby_names = Mock()
+        with patch('patroni.ha.logger.warning') as mock_logger:
+            self.ha.run_cycle()
+            mock_set_sync.assert_called_once()
+            self.assertTrue(mock_logger.call_args_list[0][0][0].startswith('Inconsistent state between '))
+        self.ha.dcs.write_sync_state = Mock(return_value=None)
+        with patch('patroni.ha.logger.warning') as mock_logger:
+            self.ha.run_cycle()
+            self.assertEqual(mock_logger.call_args[0][0], 'Updating sync state failed')
+
     def test_effective_tags(self):
         self.ha._disable_sync = True
         self.assertEqual(self.ha.get_effective_tags(), {'foo': 'bar', 'nosync': True})