正常插入,但是读取时报异常

消息: 
    System.FormatException : An error occurred while deserializing the TitleFilters property of class Czkj.AlibabaTools.XUnitTestProject.CopyBllTest+B: Value class System.ValueTuple`2[[System.Boolean, System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e],[System.Collections.Generic.List`1[[System.String, System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e]], System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e]] cannot be deserialized.
    ---- MongoDB.Bson.BsonSerializationException : Value class System.ValueTuple`2[[System.Boolean, System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e],[System.Collections.Generic.List`1[[System.String, System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e]], System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e]] cannot be deserialized.
  堆栈跟踪: 
    BsonClassMapSerializer`1.DeserializeMemberValue(BsonDeserializationContext context, BsonMemberMap memberMap)
    BsonClassMapSerializer`1.DeserializeClass(BsonDeserializationContext context)
    BsonClassMapSerializer`1.Deserialize(BsonDeserializationContext context, BsonDeserializationArgs args)
    IBsonSerializerExtensions.Deserialize[TValue](IBsonSerializer`1 serializer, BsonDeserializationContext context)
    CursorBatchDeserializationHelper.DeserializeBatch[TDocument](RawBsonArray batch, IBsonSerializer`1 documentSerializer, MessageEncoderSettings messageEncoderSettings)
    FindCommandOperation`1.CreateCursorBatch(BsonDocument commandResult)
    FindCommandOperation`1.CreateCursor(IChannelSourceHandle channelSource, BsonDocument commandResult)
    FindCommandOperation`1.ExecuteAsync(RetryableReadContext context, CancellationToken cancellationToken)
    FindOperation`1.ExecuteAsync(RetryableReadContext context, CancellationToken cancellationToken)
    FindOperation`1.ExecuteAsync(IReadBinding binding, CancellationToken cancellationToken)
    OperationExecutor.ExecuteReadOperationAsync[TResult](IReadBinding binding, IReadOperation`1 operation, CancellationToken cancellationToken)
    MongoCollectionImpl`1.ExecuteReadOperationAsync[TResult](IClientSessionHandle session, IReadOperation`1 operation, ReadPreference readPreference, CancellationToken cancellationToken)
    MongoCollectionImpl`1.UsingImplicitSessionAsync[TResult](Func`2 funcAsync, CancellationToken cancellationToken)
    IAsyncCursorSourceExtensions.FirstOrDefaultAsync[TDocument](IAsyncCursorSource`1 source, CancellationToken cancellationToken)
    CopyBllTest.InsertValueTupleTest() 行 63
    --- End of stack trace from previous location where exception was thrown ---
    ----- Inner Stack Trace -----
    BsonClassMapSerializer`1.Deserialize(BsonDeserializationContext context, BsonDeserializationArgs args)
    IBsonSerializer.Deserialize(BsonDeserializationContext context, BsonDeserializationArgs args)
    IBsonSerializerExtensions.Deserialize(IBsonSerializer serializer, BsonDeserializationContext context)
    BsonClassMapSerializer`1.DeserializeMemberValue(BsonDeserializationContext context, BsonMemberMap memberMap)

插入后的mongo数据显示如下

{ 
    "_id" : ObjectId("5db39eee71649a6e78275013"), 
    "TitleFilters" : {
        "Item1" : false, 
        "Item2" : null
    }
}

代码如下

[Fact]
        public async Task InsertValueTupleTest()
        {
            //BsonClassMap.RegisterClassMap<B>();
            var client = new MongoClient();
            var db = client.GetDatabase("alibaba_web");
            var testColloction = db.GetCollection<B>("testB");
            var filter = Builders<B>.Filter.Empty;
            await testColloction.DeleteManyAsync(filter);
            var input = new B();
            await testColloction.InsertOneAsync(input);
            var ret = await testColloction.Find(filter).FirstOrDefaultAsync();//这行报错
            Assert.NotNull(ret);
        }

        public class B
        {
            [BsonId]
            [BsonRepresentation(BsonType.ObjectId)]
            public string id { get; set; }
            //[BsonElement]
            public (bool, List<string>) TitleFilters { get; set; }
        }