Summary

A relatively simply Find document command began throwing an error after upgrading to v2.19. Works fine in v2.18

Please provide the version of the driver. If applicable, please provide the MongoDB server version and topology (standalone, replica set, or sharded cluster).

driver versions: v2.19 & v2.19.1

Server Version: 4.2,

Running on Azure.CosmosDb, but seems unrelated to the issue

How to Reproduce

            string rtn = await base.Database.Orders.Find<Order>(o =>
                o.RateBasisHistoryId == "ISSHIPZZ-GJJPU-EXSYU-9JHPE.N0P" //Not the order's BsonId but, still unique identifies an order
                )                
            .Project(r => r.Id)
            .FirstOrDefaultAsync();

The above statement throws this error:
System.FormatException: Cannot deserialize a 'String' from BsonType 'Int32'.
   at MongoDB.Bson.Serialization.Serializers.StringSerializer.DeserializeValue(BsonDeserializationContext context, BsonDeserializationArgs args)
   at MongoDB.Bson.Serialization.Serializers.SealedClassSerializerBase`1.Deserialize(BsonDeserializationContext context, BsonDeserializationArgs args)
   at MongoDB.Bson.Serialization.IBsonSerializerExtensions.Deserialize[TValue](IBsonSerializer`1 serializer, BsonDeserializationContext context)
   at MongoDB.Driver.Linq.Linq3Implementation.Serializers.WrappedValueSerializer`1.Deserialize(BsonDeserializationContext context, BsonDeserializationArgs args)
   at MongoDB.Bson.Serialization.IBsonSerializerExtensions.Deserialize[TValue](IBsonSerializer`1 serializer, BsonDeserializationContext context)
   at MongoDB.Driver.Core.Operations.CursorBatchDeserializationHelper.DeserializeBatch[TDocument](RawBsonArray batch, IBsonSerializer`1 documentSerializer, MessageEncoderSettings messageEncoderSettings)
   at MongoDB.Driver.Core.Operations.FindOperation`1.CreateFirstCursorBatch(BsonDocument cursorDocument)
   at MongoDB.Driver.Core.Operations.FindOperation`1.CreateCursor(IChannelSourceHandle channelSource, IChannelHandle channel, BsonDocument commandResult)
   at MongoDB.Driver.Core.Operations.FindOperation`1.ExecuteAsync(RetryableReadContext context, CancellationToken cancellationToken)
   at MongoDB.Driver.Core.Operations.FindOperation`1.ExecuteAsync(IReadBinding binding, CancellationToken cancellationToken)
   at MongoDB.Driver.OperationExecutor.ExecuteReadOperationAsync[TResult](IReadBinding binding, IReadOperation`1 operation, CancellationToken cancellationToken)
   at MongoDB.Driver.MongoCollectionImpl`1.ExecuteReadOperationAsync[TResult](IClientSessionHandle session, IReadOperation`1 operation, ReadPreference readPreference, CancellationToken cancellationToken)
   at MongoDB.Driver.MongoCollectionImpl`1.UsingImplicitSessionAsync[TResult](Func`2 funcAsync, CancellationToken cancellationToken)
   at MongoDB.Driver.IAsyncCursorSourceExtensions.FirstOrDefaultAsync[TDocument](IAsyncCursorSource`1 source, CancellationToken cancellationToken)

Additional Background

Removing the Projection and instead returning the entire Order object avoids the error

Order.Id is definition is:

[BsonId]
public string Id {get; set;}