Strange behavior on Windows setting file creation time

I have a strange behavior on Windows 10 Pro. I have written the following C# code, which seems to work for 2 seconds until the file (txt/pdf) changes back TO ITS ORIGINAL modification / creation time. Maybe someone can explain that to me?

static void Main(string[] args)
        {
            var filePath = args[0];
            var dateTimeStr = args[1];

            try
            {
                DateTime dateTime;
                var isOK = DateTime.TryParse(dateTimeStr,out dateTime);
                if (!isOK)
                {
                    Console.Write(string.Format("Could not parse date <{0}>! Try format <'2019-03-12 12:14:01 AM'> Exiting...", dateTimeStr));
                    return;
                }

                var fileInfo = new FileInfo(filePath);
                if (!fileInfo.Exists)
                {
                    Console.Write(string.Format("File <{0}> does not exist! Exiting...",fileInfo.FullName));
                    return;
                }
                
                Console.Write("Will set date <{0}> on file <{1}>. Continue [yY]?", fileInfo.FullName, dateTimeStr);
                var confirm = Console.ReadLine();
                if (confirm.ToLower().Contains("y"))
                {
                    // This does not work on the original file
                    File.SetLastAccessTime(fileInfo.FullName, dateTime);
                    File.SetCreationTime(fileInfo.FullName, dateTime);
                    File.SetLastWriteTime(fileInfo.FullName, dateTime);
                    Console.WriteLine("Changed date to <{0}> on file <{1}>.", fileInfo.FullName, File.GetLastWriteTime(fileInfo.FullName));
                }
                else
                {
                    Console.WriteLine("Aborted!");
                }

            }
            catch (Exception e)
            {
                Console.WriteLine("The process failed: {0}", e.ToString());
            }
}