Bug: list_filter breaks on relational walk

[Zoidmania]

Bug found in list_filter construct.
I can't use my specific application in this bug report b/c it is corporate knowledge, but I will do my best to describe it with an analogous app.

Say I have a BookCase model, and it can contain many Book models. There are many BookCases.
Book models point to a specific BookCase. I also have an Author model, which points to a specific Book (we assume an author only writes one book here). A Book may have multiple Authors.
In summary, the whole system may look something like this:

                BookCase1                         BookCase2
              /    |     \                        /        \
        Book1    Book2   Book3                 Book4       Book5
       /    |      |       \                /   |   \          \
Author1  Author2 Author3  Author4     Author5 Author6 Author7   Author8

Functions are in place to do the following:

from App.models import BookCase

# gets a specific book case
case = BookCase.objects.filter(identifier="whatever")[0]

# gets all the Books that point to this BookCase
case.books 

#--------------------------
from App.models import Book

# gets a specific book
book = Book.objects.filter(identifier="whatever")[0]

# gets the BookCase that this Book points to
case = book.case

# gets the Authors that point to this book
authors = book.authors

#--------------------------
from App.models import Author

# gets a specific Author
author = Author.objects.filter(identifier="whatever")[0]

# gets the gets the Book that this Author points to
author.book

# gets the BookCase that this Author's Book resides in
author.book__case

Now, if I want to make a model report using this tool to list all authors across all books across all book cases and filter by bookcase, I construct the following:

from App.models import BookCase, Book, Author
from model_report.report import reports, ReportAdmin
from django.utils.translation import ugettext

class AuthorData(ReportAdmin):
    title = ugettext('Book Summary')
    model = Book
    fields = [
        'book__case',
        'book__identifier',
        'book__title',
        'identifier',    # author ID in database
        'name',          # author name
        'address',       # author address
        'phone_number',  # author phone
    ]
    list_group_by = ( 'book__case',)
    list_filter = ('book__case',)  # HERE is the problem
    list_order_by = ('name',)
    type = 'report'
    exports = ('excel', 'pdf')
reports.register('AuthorData', AuthorData)

When rendering the page, I expect that filter would be a list of BookCases, but instead it is a list of Books. Furthermore, upon selecting a Book in that filter and clicking "Get results", an error is thrown saying there is no BookCase matching the filter value. I suspect this is because the parameter for that filter wants a BookCase object, but a Book is given instead, and there's a type mismatch.

[Zoidmania]

For now, in my real project, I've simply added fields that reference the parents a few hierarchical steps up. It's a temporary solution for now, but not ideal; the database just got one column larger.