C＃Mongodb FindOneAndReplace或ReplaceOne不起作用

Question

public async Task SomeWork()
        {
            Debug.WriteLine("SomeWork for User : " + Context.User.Identity.Name);
            var userProfile = await UserProfileCollection.Find(u => u._id == Context.User.Identity.Name).FirstOrDefaultAsync();

            userProfile.SuccessfullConnect = true; // currently false
            var up = await UserProfileCollection.FindOneAndReplaceAsync(u => u._id == userProfile._id, userProfile);
            Debug.WriteLine(ObjectDumper.Dump(userProfile));
            Debug.WriteLine(ObjectDumper.Dump(up));
            Debug.WriteLine("Saved SomeWork for User : " + Context.User.Identity.Name);
        }

以下是调试输出。我的文件没有被替换。 检查SuccessfullConnect变量是否仍为false。我检查服务器上也没有更换文件。有时它的工作，有时它不起作用。

SomeWork for User : +919933221101
{TestSignalR_Server.Models.UserProfile}
  _id: "+919933221101"
  ...
  SuccessfullConnect: True
  ...

{TestSignalR_Server.Models.UserProfile}
  _id: "+919933221101"
  ...
  SuccessfullConnect: False
  ...

Saved SomeWork for User : +919933221101