cluster-update rollback=False is not respected

explicitly setting the rollback=False in the following CURL request, but it cluster was rolledback.
curl -g -i -X PATCH http://xxxxx:9511/v1/clusters/k8s-cluster1/?rollback=False -H "OpenStack-API-Version: container-infra latest" -H "X-Auth-Token:-xxxxxx-xx" -H "Content-Type: application/json" -H "Accept: application/json" -H "User-Agent: None" -d '[{"path": "/node_count", "value": 2, "op": "replace"}]'

magnum cluster-list
| 5bcb7eeb-737c-46a9-9714-db6052633243 | k8s-cluster1 | testkey | 2 | 1 | UPDATE_IN_PROGRESS |

magnum cluster-list
| 5bcb7eeb-737c-46a9-9714-db6052633243 | k8s-cluster1 | testkey | 1 | 1 | ROLLBACK_IN_PROGRESS |

magnum cluster-list
| 5bcb7eeb-737c-46a9-9714-db6052633243 | k8s-cluster1 | testkey | 1 | 1 | ROLLBACK_COMPLETE |