Unable to load files in rspec when using test splitting

Build Environment
,
1

We have a circleci config something like this (pasting only the core part of it):

commands:
  setup_docker:
    steps:
      - setup_remote_docker:
          docker_layer_caching: true
          version: default
      - run:
          name: Authenticate with hub.docker.com
          command: docker login -u $GLOBAL_DOCKERHUB_USERNAME -p $GLOBAL_DOCKERHUB_PASSWORD
  setup:
    steps:
      - setup_docker
      - checkout
      - run:
          name: Make sure we are on HEAD
          command: ensure_head
      - run:
          name: Ensure clean slate
          command: ci down --remove-orphans
  build_image:
    steps:
      - run:
          name: Build CI image
          command: |
            ci build --build-arg BUNDLE_DELIVEROO__JFROG__IO
            ci tag
jobs:
  test_image:
    <<: *defaults
    parallelism: 6
    resource_class: large
    steps:
      - setup
      - build_image
      - run:
          name: Wait for Redis to start
          command: |
            ci run --rm wait wfi redis:6379 --timeout=60
      - run:
          name: Wait for DB to start
          command: |
            ci run --rm wait wfi postgres:5432 --timeout=60
      - run:
          name: DB setup
          command: |
            ci run --rm app bundle exec rails db:create db:schema:load db:migrate
      - run:
          name: Run tests
          command: |
            ci run app bundle exec rspec \
              --format RspecJunitFormatter \
              --out rspec/results.xml \
              --format progress \
              $(circleci tests glob "spec/**/*_spec.rb" | circleci tests split --split-by=timings)

      - run:
          name: Export test results from container
          when: always
          command: |
            mkdir -p $(pwd)/rspec
            docker cp app/rspec/results.xml $(pwd)/rspec/results.xml

      - store_test_results:
          path: rspec

When we run this on our pipeline occasionally, we see that loading of the test files fail. ie

An error occurred while loading ./spec/requests/policy_engine/v1/decisions_request_spec.rb. - Did you mean?
                    rspec ./spec/requests/policy_engine/decisions_request_spec.rb
                    rspec ./spec/requests/policy_engine/v1/policies_request_spec.rb
                    rspec ./spec/requests/policy_engine/v1/archives_request_spec.rb

Failure/Error: __send__(method, file)

LoadError:
  cannot load such file -- /app/spec/requests/policy_engine/v1/decisions_request_spec.rb

But we never observe this behaviour when running the test without test splitting. May I know how I can investigate more? or if this is a an already known issue?