Annoying bug in Sequel

gistfile1.rb

require "sequel"

DB = Sequel.sqlite

DB.create_table :users do
  primary_key :id
end

DB.create_table :quizzes do
  Integer :user_id
  Integer :number

  primary_key [:user_id, :number]
  foreign_key [:user_id], :users
end

DB.create_table :pages do
  Integer :user_id
  Integer :quiz_number
  Integer :number

  primary_key [:user_id, :quiz_number, :number]
  foreign_key [:user_id, :quiz_number], :quizzes
  foreign_key [:user_id], :users
end

class User < Sequel::Model
  one_to_many :quizzes
end

class Quiz < Sequel::Model
  unrestrict_primary_key

  many_to_one :user
  one_to_many :pages, :key => [:user_id, :number]
end

class Page < Sequel::Model
  unrestrict_primary_key

  many_to_one :quiz, :key => [:user_id, :quiz_number]
end

user = User.create
user.add_quiz(:number => 1).add_page(:number => 1)

user.quizzes_dataset.eager_graph(:pages).all.first       # Works
Quiz.filter(:user_id => 1).eager_graph(:pages).all.first # Fails: Sequel::DatabaseError: SQLite3::SQLException: ambiguous column name: user_id