diff --git a/common/src/main/java/com/highgo/cloud/util/CommonUtil.java b/common/src/main/java/com/highgo/cloud/util/CommonUtil.java
index 237f091..d36b51a 100644
--- a/common/src/main/java/com/highgo/cloud/util/CommonUtil.java
+++ b/common/src/main/java/com/highgo/cloud/util/CommonUtil.java
@@ -183,6 +183,7 @@ public static String unBase64(String str) {
 
     public static Date stringToDate(String dateStr) throws ParseException {
         SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'");
+        simpleDateFormat.setTimeZone(TimeZone.getTimeZone("UTC"));
         return simpleDateFormat.parse(dateStr);
     }
 
diff --git a/common/src/test/java/com/highgo/cloud/util/CommonUtilTest.java b/common/src/test/java/com/highgo/cloud/util/CommonUtilTest.java
new file mode 100644
index 0000000..74501cf
--- /dev/null
+++ b/common/src/test/java/com/highgo/cloud/util/CommonUtilTest.java
@@ -0,0 +1,74 @@
+/*
+ * 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 com.highgo.cloud.util;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+import java.text.ParseException;
+import java.time.Instant;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Date;
+import java.util.TimeZone;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.Parameterized;
+
+@RunWith(Parameterized.class)
+public class CommonUtilTest {
+    @Parameterized.Parameters(name = "{0}")
+    public static Collection<Object[]> timeZones() {
+        return Arrays.asList(new Object[][]{{"UTC"}, {"Asia/Shanghai"}, {"America/Los_Angeles"}});
+    }
+
+    private final String timeZone;
+    private TimeZone originalTimeZone;
+
+    public CommonUtilTest(String timeZone) {
+        this.timeZone = timeZone;
+    }
+
+    @Before
+    public void setTimeZone() {
+        originalTimeZone = TimeZone.getDefault();
+        TimeZone.setDefault(TimeZone.getTimeZone(timeZone));
+    }
+
+    @After
+    public void restoreTimeZone() {
+        TimeZone.setDefault(originalTimeZone);
+    }
+
+    @Test
+    public void parsesUtcTimestampIndependentlyOfDefaultTimeZone() throws ParseException {
+        assertEquals(Date.from(Instant.parse("2026-09-23T14:00:00Z")),
+                CommonUtil.stringToDate("2026-09-23T14:00:00Z"));
+    }
+
+    @Test
+    public void preservesPodStartTimeOrderingAroundInstanceUpdate() throws ParseException {
+        Date updatedAt = Date.from(Instant.parse("2026-09-23T14:00:00Z"));
+        assertTrue(CommonUtil.stringToDate("2026-09-23T13:59:59Z").before(updatedAt));
+        assertFalse(CommonUtil.stringToDate("2026-09-23T14:00:01Z").before(updatedAt));
+    }
+}