diff --git a/pkg/api/testing/defaulting_test.go b/pkg/api/testing/defaulting_test.go
index a442b14dfbf..2a08f788e29 100644
--- a/pkg/api/testing/defaulting_test.go
+++ b/pkg/api/testing/defaulting_test.go
@@ -192,24 +192,6 @@ func TestDefaulting(t *testing.T) {
 		{Group: "flowcontrol.apiserver.k8s.io", Version: "v1", Kind: "PriorityLevelConfigurationList"}:             {},
 	}
 
-	f := fuzz.New().NilChance(.5).NumElements(1, 1).RandSource(rand.NewSource(1))
-	f.Funcs(
-		func(s *runtime.RawExtension, c fuzz.Continue) {},
-		func(s *metav1.LabelSelector, c fuzz.Continue) {
-			c.FuzzNoCustom(s)
-			s.MatchExpressions = nil // need to fuzz this specially
-		},
-		func(s *metav1.ListOptions, c fuzz.Continue) {
-			c.FuzzNoCustom(s)
-			s.LabelSelector = "" // need to fuzz requirement strings specially
-			s.FieldSelector = "" // need to fuzz requirement strings specially
-		},
-		func(s *extensionsv1beta1.ScaleStatus, c fuzz.Continue) {
-			c.FuzzNoCustom(s)
-			s.TargetSelector = "" // need to fuzz requirement strings specially
-		},
-	)
-
 	scheme := legacyscheme.Scheme
 	var testTypes orderedGroupVersionKinds
 	for gvk := range scheme.AllKnownTypes() {
@@ -221,45 +203,77 @@ func TestDefaulting(t *testing.T) {
 	sort.Sort(testTypes)
 
 	for _, gvk := range testTypes {
-		_, expectedChanged := typesWithDefaulting[gvk]
-		iter := 0
-		changedOnce := false
-		for {
-			if iter > *roundtrip.FuzzIters {
-				if !expectedChanged || changedOnce {
-					break
+		gvk := gvk
+		t.Run(gvk.String(), func(t *testing.T) {
+			// Each sub-tests gets its own fuzzer instance to make running it independent
+			// from what other tests ran before.
+			f := fuzz.New().NilChance(.5).NumElements(1, 1).RandSource(rand.NewSource(1))
+			f.Funcs(
+				func(s *runtime.RawExtension, c fuzz.Continue) {},
+				func(s *metav1.LabelSelector, c fuzz.Continue) {
+					c.FuzzNoCustom(s)
+					s.MatchExpressions = nil // need to fuzz this specially
+				},
+				func(s *metav1.ListOptions, c fuzz.Continue) {
+					c.FuzzNoCustom(s)
+					s.LabelSelector = "" // need to fuzz requirement strings specially
+					s.FieldSelector = "" // need to fuzz requirement strings specially
+				},
+				func(s *extensionsv1beta1.ScaleStatus, c fuzz.Continue) {
+					c.FuzzNoCustom(s)
+					s.TargetSelector = "" // need to fuzz requirement strings specially
+				},
+			)
+
+			_, expectedChanged := typesWithDefaulting[gvk]
+			iter := 0
+			changedOnce := false
+			for {
+				if iter > *roundtrip.FuzzIters {
+					if !expectedChanged || changedOnce {
+						break
+					}
+					// This uses to be 300, but for ResourceClaimList that was not high enough
+					// because depending on the starting conditions, the fuzzer never created the
+					// one combination where defaulting kicked in (empty string in non-empty slice
+					// in another non-empty slice).
+					if iter > 3000 {
+						t.Errorf("expected %s to trigger defaulting due to fuzzing", gvk)
+						break
+					}
+					// if we expected defaulting, continue looping until the fuzzer gives us one
+					// at worst, we will timeout
 				}
-				if iter > 300 {
-					t.Errorf("expected %s to trigger defaulting due to fuzzing", gvk)
-					break
+				iter++
+
+				src, err := scheme.New(gvk)
+				if err != nil {
+					t.Fatal(err)
 				}
-				// if we expected defaulting, continue looping until the fuzzer gives us one
-				// at worst, we will timeout
-			}
-			iter++
+				f.Fuzz(src)
 
-			src, err := scheme.New(gvk)
-			if err != nil {
-				t.Fatal(err)
-			}
-			f.Fuzz(src)
+				src.GetObjectKind().SetGroupVersionKind(schema.GroupVersionKind{})
 
-			src.GetObjectKind().SetGroupVersionKind(schema.GroupVersionKind{})
+				original := src.DeepCopyObject()
 
-			original := src.DeepCopyObject()
+				// get internal
+				withDefaults := src.DeepCopyObject()
+				scheme.Default(withDefaults)
 
-			// get internal
-			withDefaults := src.DeepCopyObject()
-			scheme.Default(withDefaults.(runtime.Object))
-
-			if !reflect.DeepEqual(original, withDefaults) {
-				changedOnce = true
-				if !expectedChanged {
-					t.Errorf("{Group: \"%s\", Version: \"%s\", Kind: \"%s\"} did not expect defaults to be set - update expected or check defaulter registering: %s", gvk.Group, gvk.Version, gvk.Kind, cmp.Diff(original, withDefaults))
+				if !reflect.DeepEqual(original, withDefaults) {
+					diff := cmp.Diff(original, withDefaults)
+					if !changedOnce {
+						t.Logf("got diff (-fuzzed, +with defaults):\n%s", diff)
+						changedOnce = true
+					}
+					if !expectedChanged {
+						t.Errorf("{Group: \"%s\", Version: \"%s\", Kind: \"%s\"} did not expect defaults to be set - update expected or check defaulter registering: %s", gvk.Group, gvk.Version, gvk.Kind, diff)
+					}
 				}
 			}
-		}
+		})
 	}
+
 }
 
 func BenchmarkPodDefaulting(b *testing.B) {