diff --git a/test/e2e/apimachinery/webhook.go b/test/e2e/apimachinery/webhook.go
index b795a48ccaf..fa05c07cd01 100644
--- a/test/e2e/apimachinery/webhook.go
+++ b/test/e2e/apimachinery/webhook.go
@@ -210,9 +210,14 @@ var _ = SIGDescribe("AdmissionWebhook", func() {
 				OpenAPIV3Schema: &apiextensionsv1beta1.JSONSchemaProps{
 					Type: "object",
 					Properties: map[string]apiextensionsv1beta1.JSONSchemaProps{
-						"mutation-start":   {Type: "string"},
-						"mutation-stage-1": {Type: "string"},
-						// mutation-stage-2 is intentionally missing such that it is pruned
+						"data": {
+							Type: "object",
+							Properties: map[string]apiextensionsv1beta1.JSONSchemaProps{
+								"mutation-start":   {Type: "string"},
+								"mutation-stage-1": {Type: "string"},
+								// mutation-stage-2 is intentionally missing such that it is pruned
+							},
+						},
 					},
 				},
 			}
diff --git a/test/integration/apiserver/admissionwebhook/admission_test.go b/test/integration/apiserver/admissionwebhook/admission_test.go
index 3672eb3874f..4dd0b91d4cd 100644
--- a/test/integration/apiserver/admissionwebhook/admission_test.go
+++ b/test/integration/apiserver/admissionwebhook/admission_test.go
@@ -113,6 +113,9 @@ var (
 		gvr("", "v1", "nodes/proxy"):    {"*": testSubresourceProxy},
 		gvr("", "v1", "pods/proxy"):     {"*": testSubresourceProxy},
 		gvr("", "v1", "services/proxy"): {"*": testSubresourceProxy},
+
+		gvr("random.numbers.com", "v1", "integers"): {"create": testPruningRandomNumbers},
+		gvr("custom.fancy.com", "v2", "pants"):      {"create": testNoPruningCustomFancy},
 	}
 
 	// admissionExemptResources lists objects which are exempt from admission validation/mutation,
@@ -931,6 +934,46 @@ func testSubresourceProxy(c *testContext) {
 	}
 }
 
+func testPruningRandomNumbers(c *testContext) {
+	testResourceCreate(c)
+
+	cr2pant, err := c.client.Resource(c.gvr).Get("fortytwo", metav1.GetOptions{})
+	if err != nil {
+		c.t.Error(err)
+		return
+	}
+
+	foo, found, err := unstructured.NestedString(cr2pant.Object, "foo")
+	if err != nil {
+		c.t.Error(err)
+		return
+	}
+	if found {
+		c.t.Errorf("expected .foo to be pruned, but got: %s", foo)
+	}
+}
+
+func testNoPruningCustomFancy(c *testContext) {
+	testResourceCreate(c)
+
+	cr2pant, err := c.client.Resource(c.gvr).Get("cr2pant", metav1.GetOptions{})
+	if err != nil {
+		c.t.Error(err)
+		return
+	}
+
+	foo, _, err := unstructured.NestedString(cr2pant.Object, "foo")
+	if err != nil {
+		c.t.Error(err)
+		return
+	}
+
+	// check that no pruning took place
+	if expected, got := "test", foo; expected != got {
+		c.t.Errorf("expected /foo to be %q, got: %q", expected, got)
+	}
+}
+
 //
 // utility methods
 //