gistfile1.txt

langcode: en
status: true
dependencies: {  }
id: ya_node_article
migration_tags: null
migration_group: ya_example
label: 'Nodes (Article)'
source:
  plugin: d7_node
  node_type: article
process:
  nid: nid
  vid: vid
  langcode:
    plugin: default_value
    source: language
    default_value: und
  title: title
  # by not using plugin migration, this has potential of id collisions.
  uid: node_uid
  status: status
  created: created
  changed: changed
  promote: promote
  sticky: sticky
  revision_uid: revision_uid
  revision_log: log
  revision_timestamp: timestamp
  body: body
  # references migration ya_node_page for id migration integrity.
  field_drupal8_pages:
    plugin: migration
    migration: ya_node_page
    source: 'field_drupal7_pages/target_id'
destination:
  plugin: 'entity:node'
  default_bundle: article
migration_dependencies:
  required:
    - ya_node_page

gistfile2.txt

Results in no triangulated id.