[BUG] BsonRef does not work in 'has many' direction

[bepursuant]

Version
v5.0.21

Describe the bug
When following the instructions regarding DbRef, I can get an object to be included in the 'has one' direction, but not in the 'has many' direction. The List property is always null despite having references in the DB and the relationship working in one irection.

Code to Reproduce
The code below exhibits this behavior in the latest version of LiteDB. Post.Comments is always null.

using LiteDB;

namespace testcore
{
    public class Post
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public DateTime CreatedOn { get;set; } = DateTime.Now;

        [BsonRef]
        public List<Comment> Comments { get; set; }
    }

    public class Comment
    {
        public int Id { get; set; }
        public string Text { get; set; }
        public DateTime CreatedOn { get; set; } = DateTime.Now;

        [BsonRef]
        public Post Post { get; set; }
    }

    public class Program
    {
        static void Main(string[] args)
        {
            using (var db = new LiteDatabase("Filename=MyData.db;Connection=Shared"))
            {
                var post = new Post() {
                    Name = "Post 1"
                };
                db.GetCollection<Post>().Insert(post);

                var comment = new Comment() {
                    Text = "Comment 1",
                    Post = post
                };
                db.GetCollection<Comment>().Insert(comment);

                // "has one" relationship works with include
                var commentFromDb = db.GetCollection<Comment>().Include(c => c.Post).FindById(comment.Id);
                Console.WriteLine($"Comment from DB has {commentFromDb.Post} Post with Name {commentFromDb.Post?.Name} Name");

                // "has many" relationship does not work
                var postFromDb = db.GetCollection<Post>().Include(p => p.Comments).FindById(post.Id);
                Console.WriteLine($"Post from DB has {postFromDb.Comments} Comments List with {postFromDb.Comments?.Count} Comments");
            }
        }
    }
}

Expected behavior
Post.Comments should be a list containing the 1 related comment.

Screenshots/Stacktrace

Additional context
I've tried to specify collection names explicitly and using other types of Ids (ex. ObjectId) with the same behavior.

[bepursuant]

I did some further research on this - the example above fails in any previous version with what appears to be a circular reference, so I'd suspect the issue lies somewhere in the mapper. I know the definition is technically circular, but I thought that would be resolved by the explicit .Include() syntax.

I expected in the example for postFromDb[0].Post to be either null or just an Oid.

Are there any working tests or examples related to this functionality that I can debug through?