Carrierwave uploading file saves the file to AWS but the data doesnt persist after reload

Question

Rails 6.1 with carrierwave 1.2.3 and fog 2.1.0

I'm attaching pdfs to a Document class internally using a DocsUploader. When saved everything looks to work fine and the document is uploaded to AWS and the filename is added to the model. The prob is when i reload or retrieve the model the file and data isn't persisting.

There is another place in the code whereby i'm using the exact same uploader with a different model to upload a pdf and that works fine. Any tips on how i can debug, or what i can try as i've tried a lot of things.. it all looks to work fine but just doesn't save in the db. Here is my output and code.

    [2] pry(#<DocumentSigner>)> self.document.file

=> #<DocsUploader:0x00007fd78d9cc590
 @cache_id="1628692242-77414-0004-4934",
 @cache_storage=
  #<CarrierWave::Storage::File:0x00007fd78d9c50b0
   @cache_called=nil,
   @uploader=#<DocsUploader:0x00007fd78d9cc590 ...>>,
 @file=
  #<CarrierWave::SanitizedFile:0x00007fd78d9c6988
   @content=nil,
   @content_type="application/pdf",
   @file=
    "/Users/chrisward/Sites/***/tmp/uploads/1628692242-77414-0004-4934/B00977.pdf20210811-77414-1igeaqe.pdf",
   @original_filename="B00977.pdf20210811-77414-1igeaqe.pdf">,
 @filename="B00977.pdf20210811-77414-1igeaqe.pdf",
 @length=2,
 @model=
  #<Document:0x00007fd78b427790
   id: 114661,
   uuid: "5b400351-538d-42ca-8254-1dc22384feb2",
   title: "r bar",
   description: nil,
   file: nil,
   signed: nil,
   created_at: Wed, 11 Aug 2021 13:13:40.000000000 BST +01:00,
   updated_at: Wed, 11 Aug 2021 14:23:33.000000000 BST +01:00,
   user_id: 740,
   status: "Signed",
   qrcode: "5b400351-538d-42ca-8254-1dc22384feb2.png",
   archived: nil,
   original_file_id: 131629,
   append_signatures: true,
   pages: 2,
   additional_info: nil,
   attachment_file_id: nil,


[3] pry(#<DocumentSigner>)> self.document.save
=> true


[5] pry(#<DocumentSigner>)> self.document.file.url
=> "https://development.s3-eu-west-1.amazonaws.com/uploads/document/file/000/114/661/B00977.pdf20210811-77414-1igeaqe.pdf?X-Amz-Expires=600&X-Amz-Date=20210811T143355Z&X-Amz-Algorithm=AWS4-HMAC-SHA256"


[7] pry(#<DocumentSigner>)> self.document
=> #<Document:0x00007fd78b427790
 id: 114661,
 uuid: "5b400351-538d-42ca-8254-1dc22384feb2",
 title: "r bar",
 description: nil,
 file: "B00977.pdf20210811-77414-1igeaqe.pdf",

But after reload or retrieving from the db

[8] pry(#<DocumentSigner>)> self.document.reload
=> #<Document:0x00007fd78b427790
 id: 114661,
 uuid: "5b400351-538d-42ca-8254-1dc22384feb2",
 title: "r bar",
 description: nil,
 file: nil,

[9] pry(#<DocumentSigner>)> self.document.file.url
=> nil

** The Code **

*document.rb*

class Document < ApplicationRecord
  mount_uploader :file, DocsUploader
end


*document_signer.rb*

after_save :update_document

document.save_document({
  :stamps       => stamps,
  :labels       => labels,
  :append_cover => @document.append_signatures,
  :encrypt      => get_overall_document_status == "Signed" }) do |file|
     self.document.file = file
end

def update_document
  self.document.save!
end

*docs uploader*

# encoding: utf-8

class DocsUploader < CarrierWave::Uploader::Base

  require 'docsplit'
  require 'fileutils'

  process :set_page_count
  process :set_content_type
  before :store, :length

  def filename
    if original_filename
      converted_filename = original_filename.sub(/[^.]+\z/,"pdf")
      model.filename = converted_filename if model.instance_of?(OriginalFile)
      converted_filename
    end
  end

  def fingerprint
    Digest::SHA1.hexdigest(File.read(current_path))
  end

  def timestamp
    var = :"@#{mounted_as}_timestamp"
    model.instance_variable_get(var) or model.instance_variable_set(var, Time.now.to_i)
  end

  def cache_dir
    Rails.root.join 'tmp/uploads'
  end

  def store_dir
    "#{base_store_dir}/#{model_id_partition}"
  end

  def base_store_dir
     if Rails.env.test?
       "#{Rails.root}/spec/support"
     else
      "uploads/#{model.class.to_s.underscore}/#{mounted_as}"
     end
  end

  def model_id_partition
    ("%09d" % model.id).scan(/\d{3}/).join("/")
  end

  def extension_white_list
    %w(pdf doc docx rtf txt html ppt tiff tif xls xlsx csv key rtf numbers pages jpg jpeg png)
  end

  def pdf?
    current_path[-3,3].downcase == 'pdf'
  end

  def pdf
    current_path[0..current_path.rindex('.')] + 'pdf'
  end

  def length(file)
    if Rails.env.test?
      @length ||= 0
    else
      begin
        @length ||= Docsplit.extract_length(current_path)
      rescue Exception => e
        raise CarrierWave::ProcessingError, e.message
      end
    end
  end


  private

  def output_path
    "#{Rails.root}/tmp"
  end

  def set_content_type(*args)
    self.file.instance_variable_set(:@content_type, "application/pdf")
  end

  def set_page_count
    model.pages = length(nil) if model.has_attribute?('pages')
  end

  def secure_token
    var = :"@#{mounted_as}_secure_token"
    hash = Digest::SHA1.hexdigest("#{Time.now.to_i}#{model.id}#{read}")
    model.instance_variable_get(var) or model.instance_variable_set(var, hash)
  end
end