描述：
B/S 我在前端发了一个Post请求，后端对应的Action 执行了两遍。
背景：
.net core 2.0.0 ,EF core 2.0.0 ,sdk 2.0.0 ,nuget 包对应的也是2.0.0 版本的。
相关代码：
Program.cs

        public static void Main(string[] args)
        {
            BuildWebHost(args).Run();
        }
        public static IWebHost BuildWebHost(string[] args)
        {
            return WebHost.CreateDefaultBuilder(args)
                .ConfigureLogging((context, logging) =>
                {
                    logging.AddSerilog();
                })
                .UseStartup<Startup>()
                .Build();
        }

Startup.cs

        public Startup(IConfiguration configuration)
        {
            Configuration = configuration;

            Log.Logger = new LoggerConfiguration()
                                      .ReadFrom.Configuration(Configuration)
                                      .WriteTo.RollingFile(Path.GetFullPath("logs/log-{Date}.txt"))
                                      .CreateLogger();


        }

        public IConfiguration Configuration { get; }

        // This method gets called by the runtime. Use this method to add services to the container.
        public void ConfigureServices(IServiceCollection services)
        {
           //浏览器缓存 
            services.CacheServiceRegister();
            services.MapperInit();
            services.AddSingleton<IConfiguration>(Configuration);
            //自己写的相关服务
            services.ResiterService();
            
            services.AddDbContextPool<DbContext>(option
                        => option.UseSqlServer(Configuration.DbConnectionStr(),
                                                       o => o.UseRowNumberForPaging()));
             //memcacheCore 缓存
             services.AddEnyimMemcached(options => options.AddServer("memcached", 11211));
            services.AddCnblogsAuthentication(Configuration);

        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IHostingEnvironment env,
                              ILoggerFactory loggerFactory)
        {
           //http 重定向到https
            var rewriteOptions = new RewriteOptions();
            rewriteOptions.Rules.Add(new RedirectToProxiedHttpsRule());
            app.UseRewriter(rewriteOptions);
     
            app.UseEnyimMemcached();
            app.UseCnblogsCookieAuthentication();
            loggerFactory.AddSerilog();
            loggerFactory.AddConsole(Configuration.GetSection("Logging"));
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }
            else
            {
                app.UseCustomErrorPages();
            }

            app.UseStaticFiles();
           ///健康检查
            app.UseHealthCheck();
          //自定义Url相关代码
            app.UrlRewrite();

        }

出问题的Action

构造函数
       public EnterpriseController( 其他的service
                                    ，ILogger<EnterpriseController> log) : base(context)
        {
            _log = log;
        }

Action 
        [NeedLogin, HttpPost, ActionName("Save")]
        public async Task<IActionResult> Save(EnterpriseInfoSaveModel enterpriseInfoSaveModel)
        { 
             if(expr)
              {
              _log.LogError($"XXXXXXXX");
              }   
        }

问题出现了： 日志中出现了两个错误记录(内容都是一样的)：

2018-01-05 15:01:38.425 +09:00 [Error] XXXX
2018-01-05 15:01:38.430 +09:00 [Error] XXXX

看似一切都是正常的，就是不知道问题处在了哪里？