Keep nested attribute's values to show validation errors on form submit

Question

I have a model Parent

class Parent < ApplicationRecord
  has_many :jobs
  accepts_nested_attributes_for :jobs, allow_destroy: true
end

and model Job

class Job < ApplicationRecord
  belongs_to :parent
  belongs_to :category
  scope :for_category, ->(c) { joins(:category).where(category: { name: c }) }

  validates :destination, presence: true 
end

and the form looks like

= simple_nested_form_for @account, url: account_path, remote :true
   = f.simple_fields_for :jobs, @jobs do |jobs_form|
     = jobs_form.input :destination, as: :string

and the controller responsible looks like

class AccountsController < BaseController
  before_action :fetch_jobs

  def edit

  end

  def update
    @account.update(account_params)
    unless @account.valid?
      render :edit
    end
  end

  private
  def fetch_jobs
    @account.jobs.for_category(params['category'])
  end  
end

When the form is submitted, and the validation fails, I want to show those unsaved objects and the errors. But they are removed from @account object. I have tried doing @account.assign_attributes to do @account.save later but even assign_attributes doesn't assign attribute for nested objects. I'm guessing the scope fetches it from database instead of the object's attribute in memory.

How can I keep the nested attribute in the @account object even though the validation failed so that I can show validation errors by highlighting the nested objects in view?