Summary

When making a linq query, where you try to match a value that is a string in c# but has the attribute [BsonRepresentation(BsonType.ObjectId)] against an array of string, then you get the error: "Expression not supported: (fId == f.Id) because the two arguments are serialized differently" It was not an issue before version 3.2.0

How to Reproduce

If you have the model

public class Test
{
  [BsonId]
  [BsonRepresentation(BsonType.ObjectId)]
  public string? Id { get; set; }
}

And you then run a find like:

var client = new MongoClient();
var mongoDatabase = client.GetDatabase("Test");
var collection = mongoDatabase.GetCollection<Test>("Test");

var array = new string[] { "67b6f6aea9e81c51180d8668" };
await collection.Find(t => array.Any(id => id == t.Id)).ToListAsync();

You will get the error:

Expression not supported: (id == t.Id) because the two arguments are serialized differently.