diff --git a/logs/server.2025-09-16.0.log.gz b/logs/server.2025-09-16.0.log.gz
new file mode 100644
index 0000000..7cf7bb0
Binary files /dev/null and b/logs/server.2025-09-16.0.log.gz differ
diff --git a/src/main/java/com/gameplatform/server/mapper/agent/LinkTaskMapper.java b/src/main/java/com/gameplatform/server/mapper/agent/LinkTaskMapper.java
index 42f35be..e720093 100644
--- a/src/main/java/com/gameplatform/server/mapper/agent/LinkTaskMapper.java
+++ b/src/main/java/com/gameplatform/server/mapper/agent/LinkTaskMapper.java
@@ -33,6 +33,14 @@ public interface LinkTaskMapper extends BaseMapper<LinkTask> {
      */
     int updatePointsIfGreater(@Param("id") Long id,
                               @Param("newPoints") Integer newPoints);
+
+    /**
+     * 将指定设备上所有 LOGGED_IN 的任务标记为 COMPLETED，并写入原因与可选的完成点数。
+     * 返回受影响的行数。
+     */
+    int completeLoggedInTasksByMachine(@Param("machineId") String machineId,
+                                       @Param("reason") String reason,
+                                       @Param("completedPoints") Integer completedPoints);
     
     List<LinkTask> findByAgentId(@Param("agentId") Long agentId,
                                 @Param("size") int size,
diff --git a/src/main/java/com/gameplatform/server/model/entity/agent/LinkTask.java b/src/main/java/com/gameplatform/server/model/entity/agent/LinkTask.java
index 968adee..4c6391c 100644
--- a/src/main/java/com/gameplatform/server/model/entity/agent/LinkTask.java
+++ b/src/main/java/com/gameplatform/server/model/entity/agent/LinkTask.java
@@ -68,6 +68,9 @@ public class LinkTask {
     @TableField("completion_images")
     private String completionImages; // JSON格式存储4张图片URL
     
+    @TableField("reason")
+    private String reason; // 状态变化原因
+    
 
 
     public Long getId() { return id; }
@@ -133,5 +136,8 @@ public class LinkTask {
     public String getCompletionImages() { return completionImages; }
     public void setCompletionImages(String completionImages) { this.completionImages = completionImages; }
     
+    public String getReason() { return reason; }
+    public void setReason(String reason) { this.reason = reason; }
+    
 
 }
diff --git a/src/main/java/com/gameplatform/server/service/detection/GameCompletionDetectionService.java b/src/main/java/com/gameplatform/server/service/detection/GameCompletionDetectionService.java
index 0015f97..f77da68 100644
--- a/src/main/java/com/gameplatform/server/service/detection/GameCompletionDetectionService.java
+++ b/src/main/java/com/gameplatform/server/service/detection/GameCompletionDetectionService.java
@@ -202,6 +202,8 @@ public class GameCompletionDetectionService {
             try {
                 task.setStatus("COMPLETED");
                 task.setUpdatedAt(now);
+                // 正常检测完成：记录原因
+                task.setReason("状态：已完成");
                 
                 // 设置完成点数
                 if (points != null) {
diff --git a/src/main/java/com/gameplatform/server/service/device/DeviceStatusCheckService.java b/src/main/java/com/gameplatform/server/service/device/DeviceStatusCheckService.java
index 04cd7bd..2d2cfcf 100644
--- a/src/main/java/com/gameplatform/server/service/device/DeviceStatusCheckService.java
+++ b/src/main/java/com/gameplatform/server/service/device/DeviceStatusCheckService.java
@@ -71,12 +71,28 @@ public class DeviceStatusCheckService {
             DeviceStatusInfo statusInfo = parseDeviceStatus(deviceStatus);
             log.debug("设备 {} 状态解析结果: {}", machineId, statusInfo);
             
-            // 3. 如果设备空闲，通过完成检测服务进行判定（含缓冲与二次确认）
+            // 3. 如果设备空闲，通过完成检测服务进行判定（含缓冲与二次确认）。
+            // 若未能直接判定完成，则执行兜底：将该设备上 LOGGED_IN 的任务批量置为 COMPLETED，并写入原因。
             if (statusInfo.isIdle()) {
                 String source = "TIMER_TASK";
                 com.gameplatform.server.util.AuditLogger.debug("IdleDetected: device={}, source={}, status={}, points={}", machineId, source, statusInfo.getStatus(), statusInfo.getPoints());
                 // 调用完成检测服务（包含登录缓冲与二次确认）
-                completionDetectionService.detectGameCompletion(machineId, statusInfo.getStatus(), source);
+                boolean done = completionDetectionService.detectGameCompletion(machineId, statusInfo.getStatus(), source);
+                if (!done) {
+                    // 兜底完成：当设备空闲，直接将 LOGGED_IN 任务置为完成
+                    String completionReason = "状态：已完成（空闲兜底）";
+                    Integer points = statusInfo.getPoints();
+                    try {
+                        int affected = linkTaskMapper.completeLoggedInTasksByMachine(machineId, completionReason, points);
+                        if (affected > 0) {
+                            log.info("空闲兜底：设备 {} 完成了 {} 个任务，reason='{}' points={} ", machineId, affected, completionReason, points);
+                        } else {
+                            log.debug("空闲兜底：设备 {} 无需更新（无 LOGGED_IN 任务）", machineId);
+                        }
+                    } catch (Exception e) {
+                        log.warn("空闲兜底完成失败 device={} err={}", machineId, e.getMessage());
+                    }
+                }
             } else {
                 log.debug("设备 {} 状态为 [{}]，非空闲状态，跳过检查", machineId, statusInfo.getStatus());
             }
diff --git a/src/main/resources/mapper/agent/LinkTaskMapper.xml b/src/main/resources/mapper/agent/LinkTaskMapper.xml
index 169af7b..8bc3cb0 100644
--- a/src/main/resources/mapper/agent/LinkTaskMapper.xml
+++ b/src/main/resources/mapper/agent/LinkTaskMapper.xml
@@ -23,24 +23,25 @@
         <result property="firstRegionSelectAt" column="first_region_select_at" />
         <result property="completedPoints" column="completed_points" />
         <result property="completionImages" column="completion_images" />
+        <result property="reason" column="reason" />
     </resultMap>
 
     <select id="findById" parameterType="long" resultMap="LinkTaskMap">
-        SELECT id, batch_id, agent_id, code_no, token_hash, expire_at, status, region, machine_id, login_at, refund_at, revoked_at, created_at, updated_at, need_refresh, refresh_time, qr_created_at, qr_expire_at, first_region_select_at, completed_points, completion_images
+        SELECT id, batch_id, agent_id, code_no, token_hash, expire_at, status, region, machine_id, login_at, refund_at, revoked_at, created_at, updated_at, need_refresh, refresh_time, qr_created_at, qr_expire_at, first_region_select_at, completed_points, completion_images, reason
         FROM link_task
         WHERE id = #{id}
         LIMIT 1
     </select>
 
     <select id="findByCodeNo" parameterType="string" resultMap="LinkTaskMap">
-        SELECT id, batch_id, agent_id, code_no, token_hash, expire_at, status, region, machine_id, login_at, refund_at, revoked_at, created_at, updated_at, need_refresh, refresh_time, qr_created_at, qr_expire_at, first_region_select_at, completed_points, completion_images
+        SELECT id, batch_id, agent_id, code_no, token_hash, expire_at, status, region, machine_id, login_at, refund_at, revoked_at, created_at, updated_at, need_refresh, refresh_time, qr_created_at, qr_expire_at, first_region_select_at, completed_points, completion_images, reason
         FROM link_task
         WHERE code_no = #{codeNo}
         LIMIT 1
     </select>
 
     <select id="findByTokenHash" parameterType="string" resultMap="LinkTaskMap">
-        SELECT id, batch_id, agent_id, code_no, token_hash, expire_at, status, region, machine_id, login_at, refund_at, revoked_at, created_at, updated_at, need_refresh, refresh_time, qr_created_at, qr_expire_at, first_region_select_at, completed_points, completion_images
+        SELECT id, batch_id, agent_id, code_no, token_hash, expire_at, status, region, machine_id, login_at, refund_at, revoked_at, created_at, updated_at, need_refresh, refresh_time, qr_created_at, qr_expire_at, first_region_select_at, completed_points, completion_images, reason
         FROM link_task
         WHERE token_hash = #{tokenHash}
         LIMIT 1
@@ -67,6 +68,7 @@
             <if test="firstRegionSelectAt != null">first_region_select_at = #{firstRegionSelectAt},</if>
             <if test="completedPoints != null">completed_points = #{completedPoints},</if>
             <if test="completionImages != null">completion_images = #{completionImages},</if>
+            <if test="reason != null">reason = #{reason},</if>
             updated_at = NOW()
         </set>
         WHERE id = #{id}
@@ -90,6 +92,19 @@
           AND (completed_points IS NULL OR completed_points &lt; #{newPoints})
     </update>
 
+    <!-- 将指定设备的 LOGGED_IN 任务批量置为 COMPLETED，写入原因与可选点数 -->
+    <update id="completeLoggedInTasksByMachine">
+        UPDATE link_task
+        <set>
+            status = 'COMPLETED',
+            reason = #{reason},
+            <if test="completedPoints != null">completed_points = #{completedPoints},</if>
+            updated_at = NOW()
+        </set>
+        WHERE machine_id = #{machineId}
+          AND status = 'LOGGED_IN'
+    </update>
+
     <select id="findByAgentId" resultMap="LinkTaskMap">
         SELECT id, batch_id, agent_id, code_no, token_hash, expire_at, status, region, machine_id, login_at, refund_at, revoked_at, created_at, updated_at, need_refresh, refresh_time, qr_created_at, qr_expire_at, first_region_select_at, completed_points, completion_images
         FROM link_task