Paper trail not writing destroy events for join table soft deletes

Question

I'm using paper trail in my app partially to display an audit log of changes and have noticed that it won't track destroy events when items in join tables are soft deleted (it works fine for other tables). I have a model that looks something like this:

module Book
  class BookGenre < ApplicationRecord
    acts_as_paranoid
    has_paper_trail

    belongs_to :book, inverse_of: :book_genres
    belongs_to :genre

    validates :book, presence: true
    validates :genre, presence: true
  end
end

# == Schema Information
#
# Table name: book_genres
#
#  id            :bigint           not null, primary key
#  deleted_at    :datetime
#  created_at    :datetime         not null
#  updated_at    :datetime         not null
#  genre_id      :integer          not null
#  book_id       :integer          not null
#

Changes to this table are made through the update method in the "book" controller. When a "genre" is removed from a book paper trail doesn't write anything to the versions table, so these events are not properly tracked.

For a model that looks something like this it tracks both create and destroy events as expected when updating though the same "book" controller method:

module Book
  class Cover < ApplicationRecord
    acts_as_paranoid
    has_paper_trail

    belongs_to :book

    validates :book, presence: true
    validates :cover_link, presence: true
  end
end

# == Schema Information
#
# Table name: book_genres
#
#  id            :bigint           not null, primary key
#  deleted_at    :datetime
#  created_at    :datetime         not null
#  updated_at    :datetime         not null
#  book_id       :integer          not null
#  cover_link    :string           not null 
#

My hunch is that this has something to with the fact that "book_genres" is a join table. Any ideas on how to get this working the way I want?

I've tried:

• Explicitly telling paper trail to track destroy operations instead of relying on defaults with has_paper_trail :on => [:update, :create, :destroy]
• Installing and setting up the paper_trail-association_tracking gem
• Upgrading paper trail to the latest version
• Read through the paper trail docs and not found what I'm looking for (although maybe I missed it)