diff --git a/tenant-service/src/main/java/com/xuqm/tenant/service/SystemUpdateService.java b/tenant-service/src/main/java/com/xuqm/tenant/service/SystemUpdateService.java
index 1a9cefc..4cb632e 100644
--- a/tenant-service/src/main/java/com/xuqm/tenant/service/SystemUpdateService.java
+++ b/tenant-service/src/main/java/com/xuqm/tenant/service/SystemUpdateService.java
@@ -899,8 +899,12 @@ public class SystemUpdateService {
      */
     private String getNewestContainerId(String service) {
         try {
+            // Do NOT use -n 1: Docker applies -n globally before the label filter,
+            // so if the last-created container is a different service, the filter
+            // returns empty. Without -n, docker ps sorts newest-first and the
+            // label filter returns only this service's containers.
             Process p = new ProcessBuilder(
-                    "docker", "ps", "-a", "-n", "1",
+                    "docker", "ps", "-a",
                     "--filter", "label=com.docker.compose.service=" + service,
                     "--format", "{{.ID}}"
             ).redirectErrorStream(true).start();