This operation will update the correct row, but will also create a duplicate of that row. How do I prevent this behavior ?

        public bool Update(UserModel entity)
        {
            using (var db = new LiteDatabase(_connectionString))
            {
                var col = db.GetCollection<UserModel>();
                var result = col.Update(entity);
                return result;
            }
        }

For reference, UserModel looks like this :

public class UserModel
{
    [BsonId]
    public int Id { get; set; }

    public string? UserName { get; set; }

    /* Some more fields without annotations*/
}

I’ve tried with and without the [BsonId] annotation.