DateTime.Now.AddDays(-1).ToString("yyyy-MM")

改为
DateTime.Now.AddMonths(-1).ToString("yyyy-MM")

AppStart/Helper/StatService.cs

@@ -1989,7 +1989,7 @@ namespace MySystem
             {
                 if(DateTime.Now.Day < 15 && DateTime.Now.Hour >= 0)
                 {
-                    string Month = DateTime.Now.AddDays(-1).ToString("yyyy-MM");
+                    string Month = DateTime.Now.AddMonths(-1).ToString("yyyy-MM");
                     string flag = function.ReadInstance("/ProfitFlag/" + Month + ".txt");
                     if (string.IsNullOrEmpty(flag))
                     {