diff --git a/cmd/kube-apiserver/app/aggregator.go b/cmd/kube-apiserver/app/aggregator.go
index 6c0c23f83bb..30f3b01915e 100644
--- a/cmd/kube-apiserver/app/aggregator.go
+++ b/cmd/kube-apiserver/app/aggregator.go
@@ -120,6 +120,9 @@ func createAggregatorConfig(
 		},
 	}
 
+	// we need to clear the poststarthooks so we don't add them multiple times to all the servers (that fails)
+	aggregatorConfig.GenericConfig.PostStartHooks = map[string]genericapiserver.PostStartHookConfigEntry{}
+
 	return aggregatorConfig, nil
 }
 
diff --git a/cmd/kube-apiserver/app/apiextensions.go b/cmd/kube-apiserver/app/apiextensions.go
index c2f8dab4ffd..438e8588c2b 100644
--- a/cmd/kube-apiserver/app/apiextensions.go
+++ b/cmd/kube-apiserver/app/apiextensions.go
@@ -92,6 +92,9 @@ func createAPIExtensionsConfig(
 		},
 	}
 
+	// we need to clear the poststarthooks so we don't add them multiple times to all the servers (that fails)
+	apiextensionsConfig.GenericConfig.PostStartHooks = map[string]genericapiserver.PostStartHookConfigEntry{}
+
 	return apiextensionsConfig, nil
 }