diff --git a/etcd/vendor/github.com/openshift/microshift/pkg/config/apiserver.go b/etcd/vendor/github.com/openshift/microshift/pkg/config/apiserver.go
index 54f6b29129..3bde9b4052 100644
--- a/etcd/vendor/github.com/openshift/microshift/pkg/config/apiserver.go
+++ b/etcd/vendor/github.com/openshift/microshift/pkg/config/apiserver.go
@@ -191,6 +191,9 @@ func (fg *FeatureGates) validateFeatureGates() error {
 
 	switch fg.FeatureSet {
 	case "":
+		if len(fg.CustomNoUpgrade.Enabled) > 0 || len(fg.CustomNoUpgrade.Disabled) > 0 {
+			return fmt.Errorf("CustomNoUpgrade enabled/disabled lists must be empty when FeatureSet is empty")
+		}
 		return nil
 	case FeatureSetCustomNoUpgrade:
 		// Valid - continue with validation
diff --git a/pkg/config/apiserver.go b/pkg/config/apiserver.go
index 54fb5b18dc..a82fa49f94 100644
--- a/pkg/config/apiserver.go
+++ b/pkg/config/apiserver.go
@@ -194,6 +194,9 @@ func (fg *FeatureGates) validateFeatureGates() error {
 
 	switch fg.FeatureSet {
 	case "":
+		if len(fg.CustomNoUpgrade.Enabled) > 0 || len(fg.CustomNoUpgrade.Disabled) > 0 {
+			return fmt.Errorf("CustomNoUpgrade enabled/disabled lists must be empty when FeatureSet is empty")
+		}
 		return nil
 	case FeatureSetCustomNoUpgrade:
 		// Valid - continue with validation
diff --git a/pkg/config/config_test.go b/pkg/config/config_test.go
index e2460a8002..79d9612daa 100644
--- a/pkg/config/config_test.go
+++ b/pkg/config/config_test.go
@@ -827,7 +827,7 @@ func TestValidate(t *testing.T) {
 				c.ApiServer.FeatureGates.CustomNoUpgrade.Disabled = []string{"feature2"}
 				return c
 			}(),
-			expectErr: false,
+			expectErr: true,
 		},
 		{
 			name: "feature-gates-custom-no-upgrade-valid",