diff --git a/controllers/spec/hpa.go b/controllers/spec/hpa.go
index 9884d878..5f3833d4 100644
--- a/controllers/spec/hpa.go
+++ b/controllers/spec/hpa.go
@@ -29,7 +29,7 @@ type BuiltinAutoScaler interface {
 }
 
 func isDefaultHPAEnabled(minReplicas, maxReplicas *int32, podPolicy v1alpha1.PodPolicy) bool {
-	return minReplicas != nil && maxReplicas != nil && podPolicy.AutoScalingBehavior == nil && len(podPolicy.AutoScalingMetrics) == 0 && len(podPolicy.BuiltinAutoscaler) == 0 && *maxReplicas > *minReplicas
+	return minReplicas != nil && maxReplicas != nil && podPolicy.AutoScalingBehavior == nil && len(podPolicy.AutoScalingMetrics) == 0 && len(podPolicy.BuiltinAutoscaler) == 0
 }
 
 func isBuiltinHPAEnabled(minReplicas, maxReplicas *int32, podPolicy v1alpha1.PodPolicy) bool {
diff --git a/controllers/spec/hpa_test.go b/controllers/spec/hpa_test.go
new file mode 100644
index 00000000..6577cbf2
--- /dev/null
+++ b/controllers/spec/hpa_test.go
@@ -0,0 +1,50 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+package spec
+
+import (
+	"testing"
+
+	"github.com/streamnative/function-mesh/api/compute/v1alpha1"
+	"github.com/stretchr/testify/require"
+	autov2 "k8s.io/api/autoscaling/v2"
+	corev1 "k8s.io/api/core/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+)
+
+func TestFixedReplicaHPADoesNotDriftAfterAPIDefaulting(t *testing.T) {
+	replicas := int32(1)
+	desired := MakeHPA(&metav1.ObjectMeta{Name: "fixed"}, autov2.CrossVersionObjectReference{
+		APIVersion: "compute.functionmesh.io/v1alpha1", Kind: "Function", Name: "fixed",
+	}, &replicas, &replicas, v1alpha1.PodPolicy{}, corev1.ResourceRequirements{})
+
+	// Kubernetes supplies CPU utilization 80 when an HPA has no metrics.
+	persisted := desired.DeepCopy()
+	if len(persisted.Spec.Metrics) == 0 {
+		utilization := int32(80)
+		persisted.Spec.Metrics = []autov2.MetricSpec{{
+			Type: autov2.ResourceMetricSourceType,
+			Resource: &autov2.ResourceMetricSource{
+				Name:   corev1.ResourceCPU,
+				Target: autov2.MetricTarget{Type: autov2.UtilizationMetricType, AverageUtilization: &utilization},
+			},
+		}}
+	}
+	require.True(t, CheckIfHPASpecIsEqual(&persisted.Spec, &desired.Spec))
+	require.Equal(t, int32(1), desired.Spec.MaxReplicas)
+}