Searchkick::ImportError "no such index"

Question

I have a Rails application hosted in Heroku and it uses the searchkick gem version 4.6.1. I'm using Bonsai add-on.

I only have one model that uses searchkick:

class Program < ApplicationRecord
  searchkick

  # blah blah blah

  scope :search_import, -> { includes(:provider, :categories, :address, :current_published_schedules) }

    def search_data
    {
      name: name,
      description: description,
      provider_name: name,
      categories: categories.pluck(:name),
      start_dates: current_published_schedules.pluck(:start_date).sort,
      registration_opens_at: current_published_schedules.pluck(:registration_opens_at),
      registration_closes_at: current_published_schedules.pluck(:registration_closes_at),
      city: address&.city,
      state: address&.state,
      zipcode: address&.zipcode,
      program_type: program_type
    }
  end

  def should_index?
    published?
  end

I have this rake task:

namespace :searchkick do
  desc "Reindex models"
  task reindex: :environment do
    Searchkick::ReindexWorker.perform_async
  end
end

and this worker:

module Searchkick
  class ReindexWorker
    include Sidekiq::Worker

    sidekiq_options retry: 3

    def perform
      Program.reindex
    end
  end
end

My procfile is:

release: bash ./release-tasks.sh
web: bundle exec puma -t 5:5 -p ${PORT:-3000} -e ${RACK_ENV:-development}
worker: bundle exec sidekiq -q default -q low -c 2
clock: bundle exec clockwork config/clock.rb

and release-tasks.sh looks like this:

echo "Running Release Tasks"

echo "Migrating:"
bundle exec rake db:migrate

echo "Indexing (searchkick):"
bundle exec rake searchkick:reindex

When I deploy, I occasionally see the following error in my error monitoring tool:

Searchkick::ImportErrorsearchkick:index
{"type"=>"index_not_found_exception", "reason"=>"no such index [programs_production_20230321124906238]", "index_uuid"=>"Yn2PekrDRvi6ZUI6H1cflg", "index"=>"programs_producti ...

When I run

heroku run bundle exec rake searchkick:reindex --app my-prod-app

it runs fine.

I don't understand how indexes work. I am overwhelmed by the amount of information so I don't even know where to start looking.

Questions:

1. Is there anything wrong with my setup that would be causing this issue?
2. Is Program.reindex what I should be running after deploy or should this be something else?
3. Why does the index have a timestamp? (noob elastic-search question, I come from postgres background where indexes just have a name). Why would it not find it?