diff --git a/api/bootstrap/kubeadm/v1beta1/conversion_test.go b/api/bootstrap/kubeadm/v1beta1/conversion_test.go
index 371864ea86a9..46fa8f6eb105 100644
--- a/api/bootstrap/kubeadm/v1beta1/conversion_test.go
+++ b/api/bootstrap/kubeadm/v1beta1/conversion_test.go
@@ -218,6 +218,16 @@ func spokeKubeadmConfigSpec(in *KubeadmConfigSpec, c randfill.Continue) {
 		}
 		in.Users[i] = user
 	}
+
+	if reflect.DeepEqual(in.ClusterConfiguration, &ClusterConfiguration{}) {
+		in.ClusterConfiguration = nil
+	}
+	if reflect.DeepEqual(in.InitConfiguration, &InitConfiguration{}) {
+		in.InitConfiguration = nil
+	}
+	if reflect.DeepEqual(in.JoinConfiguration, &JoinConfiguration{}) {
+		in.JoinConfiguration = nil
+	}
 }
 
 func spokeClusterConfiguration(in *ClusterConfiguration, c randfill.Continue) {
diff --git a/api/controlplane/kubeadm/v1beta1/conversion_test.go b/api/controlplane/kubeadm/v1beta1/conversion_test.go
index e58dc265cf51..a9c6fff07f13 100644
--- a/api/controlplane/kubeadm/v1beta1/conversion_test.go
+++ b/api/controlplane/kubeadm/v1beta1/conversion_test.go
@@ -345,6 +345,16 @@ func spokeKubeadmConfigSpec(in *bootstrapv1beta1.KubeadmConfigSpec, c randfill.C
 		}
 		in.Users[i] = user
 	}
+
+	if reflect.DeepEqual(in.ClusterConfiguration, &bootstrapv1beta1.ClusterConfiguration{}) {
+		in.ClusterConfiguration = nil
+	}
+	if reflect.DeepEqual(in.InitConfiguration, &bootstrapv1beta1.InitConfiguration{}) {
+		in.InitConfiguration = nil
+	}
+	if reflect.DeepEqual(in.JoinConfiguration, &bootstrapv1beta1.JoinConfiguration{}) {
+		in.JoinConfiguration = nil
+	}
 }
 
 func spokeClusterConfiguration(in *bootstrapv1beta1.ClusterConfiguration, c randfill.Continue) {
diff --git a/internal/api/bootstrap/kubeadm/v1alpha3/conversion_test.go b/internal/api/bootstrap/kubeadm/v1alpha3/conversion_test.go
index f2ba89b16d9e..2ba3cb3625b9 100644
--- a/internal/api/bootstrap/kubeadm/v1alpha3/conversion_test.go
+++ b/internal/api/bootstrap/kubeadm/v1alpha3/conversion_test.go
@@ -190,6 +190,16 @@ func spokeKubeadmConfigSpec(in *KubeadmConfigSpec, c randfill.Continue) {
 		}
 		in.Files[i] = file
 	}
+
+	if reflect.DeepEqual(in.ClusterConfiguration, &ClusterConfiguration{}) {
+		in.ClusterConfiguration = nil
+	}
+	if reflect.DeepEqual(in.InitConfiguration, &InitConfiguration{}) {
+		in.InitConfiguration = nil
+	}
+	if reflect.DeepEqual(in.JoinConfiguration, &JoinConfiguration{}) {
+		in.JoinConfiguration = nil
+	}
 }
 
 func spokeKubeadmConfigStatus(obj *KubeadmConfigStatus, c randfill.Continue) {
diff --git a/internal/api/bootstrap/kubeadm/v1alpha4/conversion_test.go b/internal/api/bootstrap/kubeadm/v1alpha4/conversion_test.go
index 5dee48eea353..68e20a751d8d 100644
--- a/internal/api/bootstrap/kubeadm/v1alpha4/conversion_test.go
+++ b/internal/api/bootstrap/kubeadm/v1alpha4/conversion_test.go
@@ -188,6 +188,16 @@ func spokeKubeadmConfigSpec(in *KubeadmConfigSpec, c randfill.Continue) {
 		}
 		in.Files[i] = file
 	}
+
+	if reflect.DeepEqual(in.ClusterConfiguration, &ClusterConfiguration{}) {
+		in.ClusterConfiguration = nil
+	}
+	if reflect.DeepEqual(in.InitConfiguration, &InitConfiguration{}) {
+		in.InitConfiguration = nil
+	}
+	if reflect.DeepEqual(in.JoinConfiguration, &JoinConfiguration{}) {
+		in.JoinConfiguration = nil
+	}
 }
 
 func spokeKubeadmConfigStatus(obj *KubeadmConfigStatus, c randfill.Continue) {
diff --git a/internal/api/controlplane/kubeadm/v1alpha3/conversion_test.go b/internal/api/controlplane/kubeadm/v1alpha3/conversion_test.go
index e6cad60c707a..24b0752dc7d1 100644
--- a/internal/api/controlplane/kubeadm/v1alpha3/conversion_test.go
+++ b/internal/api/controlplane/kubeadm/v1alpha3/conversion_test.go
@@ -277,6 +277,16 @@ func spokeKubeadmConfigSpec(in *bootstrapv1alpha3.KubeadmConfigSpec, c randfill.
 		}
 		in.Files[i] = file
 	}
+
+	if reflect.DeepEqual(in.ClusterConfiguration, &bootstrapv1alpha3.ClusterConfiguration{}) {
+		in.ClusterConfiguration = nil
+	}
+	if reflect.DeepEqual(in.InitConfiguration, &bootstrapv1alpha3.InitConfiguration{}) {
+		in.InitConfiguration = nil
+	}
+	if reflect.DeepEqual(in.JoinConfiguration, &bootstrapv1alpha3.JoinConfiguration{}) {
+		in.JoinConfiguration = nil
+	}
 }
 
 func spokeAPIServer(in *bootstrapv1alpha3.APIServer, c randfill.Continue) {
diff --git a/internal/api/controlplane/kubeadm/v1alpha4/conversion_test.go b/internal/api/controlplane/kubeadm/v1alpha4/conversion_test.go
index 1ac9a1e28611..13a2c2b61a5a 100644
--- a/internal/api/controlplane/kubeadm/v1alpha4/conversion_test.go
+++ b/internal/api/controlplane/kubeadm/v1alpha4/conversion_test.go
@@ -302,6 +302,16 @@ func spokeKubeadmConfigSpec(in *bootstrapv1alpha4.KubeadmConfigSpec, c randfill.
 		}
 		in.Files[i] = file
 	}
+
+	if reflect.DeepEqual(in.ClusterConfiguration, &bootstrapv1alpha4.ClusterConfiguration{}) {
+		in.ClusterConfiguration = nil
+	}
+	if reflect.DeepEqual(in.InitConfiguration, &bootstrapv1alpha4.InitConfiguration{}) {
+		in.InitConfiguration = nil
+	}
+	if reflect.DeepEqual(in.JoinConfiguration, &bootstrapv1alpha4.JoinConfiguration{}) {
+		in.JoinConfiguration = nil
+	}
 }
 
 func spokeClusterConfiguration(in *bootstrapv1alpha4.ClusterConfiguration, c randfill.Continue) {