Can mounted collections use {parent_uri} when building their urls or must you explicitly set it in the collection.yaml?

Simplified version of the problem, two collections below. Note, news is mounted to a "Pages" entity who's slug is "news"

# pages.yaml
title: Pages
template: template
blueprints:
  - default
revisions: true
route: '/{parent_uri}/{slug}'
date: true
sort_dir: asc
default_status: draft
date_behavior:
  past: public
  future: private
structure:
  root: true
  tree:
    -
      entry: 1c8c9454-ed8a-430f-afc1-de338ccfd6f0
# news.yaml
title: News
template: template
blueprints:
  - news
mount: 1c8c9454-ed8a-430f-afc1-de338ccfd6f0
revisions: true
route: '{parent_uri}/{slug}'
date: true
sort_dir: desc
date_behavior:
  past: public
  future: private

Expected url of News entities: /news/{slug} Actual url of News entities: /{slug}

All News entities don't appear to be inheriting the mounted Entities uri. From looking at the code this is by design as when I load an Entity using the EntityRepository it does not have a parent value.