diff --git a/machine/v1beta1/manual-override-crd-manifests/machines.machine.openshift.io/MachineAPIMigration.yaml b/machine/v1beta1/manual-override-crd-manifests/machines.machine.openshift.io/MachineAPIMigration.yaml
index f0ca33e37a3..bc2f39aaf95 100644
--- a/machine/v1beta1/manual-override-crd-manifests/machines.machine.openshift.io/MachineAPIMigration.yaml
+++ b/machine/v1beta1/manual-override-crd-manifests/machines.machine.openshift.io/MachineAPIMigration.yaml
@@ -21,3 +21,5 @@ spec:
                 && self.synchronizedGeneration >= oldSelf.synchronizedGeneration)
                 || (oldSelf.authoritativeAPI == ''Migrating'' && self.authoritativeAPI
                 != ''Migrating'')'
+            - message: authoritativeAPI may not be removed once set
+              rule: has(self.authoritativeAPI) || !has(oldSelf.authoritativeAPI)
diff --git a/machine/v1beta1/manual-override-crd-manifests/machinesets.machine.openshift.io/MachineAPIMigration.yaml b/machine/v1beta1/manual-override-crd-manifests/machinesets.machine.openshift.io/MachineAPIMigration.yaml
index 2f78133cba3..8cd4700d7f7 100644
--- a/machine/v1beta1/manual-override-crd-manifests/machinesets.machine.openshift.io/MachineAPIMigration.yaml
+++ b/machine/v1beta1/manual-override-crd-manifests/machinesets.machine.openshift.io/MachineAPIMigration.yaml
@@ -21,3 +21,5 @@ spec:
                 && self.synchronizedGeneration >= oldSelf.synchronizedGeneration)
                 || (oldSelf.authoritativeAPI == ''Migrating'' && self.authoritativeAPI
                 != ''Migrating'')'
+            - message: authoritativeAPI may not be removed once set
+              rule: has(self.authoritativeAPI) || !has(oldSelf.authoritativeAPI)
diff --git a/tools/codegen/pkg/manifestmerge/crd-schema.json b/tools/codegen/pkg/manifestmerge/crd-schema.json
index 0fe236e86aa..03a3d3ce832 100644
--- a/tools/codegen/pkg/manifestmerge/crd-schema.json
+++ b/tools/codegen/pkg/manifestmerge/crd-schema.json
@@ -727,12 +727,7 @@
               "default": {}
             },
             "type": "array",
-            "x-kubernetes-list-map-keys": [
-              "rule"
-            ],
-            "x-kubernetes-list-type": "map",
-            "x-kubernetes-patch-merge-key": "rule",
-            "x-kubernetes-patch-strategy": "merge"
+            "x-kubernetes-list-type": "atomic"
           }
         },
         "type": "object"