修复

internal/task/polling_base.go

@@ -29,6 +29,17 @@ var acquireConcurrencyScript = redis.NewScript(`
     return current
 `)
 
+var releaseConcurrencyScript = redis.NewScript(`
+    local current = tonumber(redis.call('GET', KEYS[1]) or '0') or 0
+    if current <= 0 then
+        if redis.call('EXISTS', KEYS[1]) == 1 then
+            redis.call('SET', KEYS[1], 0, 'KEEPTTL')
+        end
+        return 0
+    end
+    return redis.call('DECR', KEYS[1])
+`)
+
 const pollingFallbackOperationTimeout = 5 * time.Second
 
 // pollingFallbackContext 创建轮询兜底操作使用的独立短超时上下文。
@@ -101,7 +112,7 @@ func (b *PollingBase) releaseConcurrency(_ context.Context, taskType string) {
 	defer cancel()
 
 	currentKey := constants.RedisPollingConcurrencyCurrentKey(taskType)
-	if err := b.redis.Decr(ctx, currentKey).Err(); err != nil {
+	if err := releaseConcurrencyScript.Run(ctx, b.redis, []string{currentKey}).Err(); err != nil {
 		b.logger.Warn("释放并发计数失败", zap.String("task_type", taskType), zap.Error(err))
 	}
 }