diff --git a/ironic/api/controllers/v1/node.py b/ironic/api/controllers/v1/node.py
index 1eb03fd7e0..f9531cad2d 100644
--- a/ironic/api/controllers/v1/node.py
+++ b/ironic/api/controllers/v1/node.py
@@ -1766,6 +1766,11 @@ class NodesController(rest.RestController):
                 continue
             if patch_val == wtypes.Unset:
                 patch_val = None
+            # conductor_group is case-insensitive, and we use it to calculate
+            # the conductor to send an update too. lowercase it here instead
+            # of just before saving so we calculate correctly.
+            if field == 'conductor_group':
+                patch_val = patch_val.lower()
             if rpc_node[field] != patch_val:
                 rpc_node[field] = patch_val
 
diff --git a/ironic/tests/unit/api/controllers/v1/test_node.py b/ironic/tests/unit/api/controllers/v1/test_node.py
index 15e01ddd50..c76c11e699 100644
--- a/ironic/tests/unit/api/controllers/v1/test_node.py
+++ b/ironic/tests/unit/api/controllers/v1/test_node.py
@@ -2324,6 +2324,19 @@ class TestPatch(test_api_base.BaseApiTest):
         self.assertEqual(http_client.NOT_ACCEPTABLE, response.status_code)
         self.assertTrue(response.json['error_message'])
 
+    @mock.patch('pecan.request')
+    def test__update_changed_fields_lowers_conductor_group(self,
+                                                           mock_pecan_req):
+        mock_pecan_req.version.minor = versions.MINOR_MAX_VERSION
+        controller = api_node.NodesController()
+
+        node_dict = self.node.as_dict()
+        node_dict['conductor_group'] = 'NEW-GROUP'
+        node_obj = api_node.Node(**node_dict)
+
+        controller._update_changed_fields(node_obj, self.node)
+        self.assertEqual('new-group', self.node.conductor_group)
+
     @mock.patch("pecan.request")
     def test__update_changed_fields_remove_chassis_uuid(self, mock_pecan_req):
         mock_pecan_req.version.minor = versions.MINOR_MAX_VERSION
diff --git a/releasenotes/notes/bug-2004947-e5f27e11b8f9c96d.yaml b/releasenotes/notes/bug-2004947-e5f27e11b8f9c96d.yaml
new file mode 100644
index 0000000000..4af981224d
--- /dev/null
+++ b/releasenotes/notes/bug-2004947-e5f27e11b8f9c96d.yaml
@@ -0,0 +1,6 @@
+---
+fixes:
+  - |
+    Fixes an issue where setting the ``conductor_group`` for a node was not
+    entirely case-sensitive, in that this could fail if case-sensitivity did
+    not match between the conductor configuration and the API request.