Using nested wiki pages in Gitlab CE throws a 500 error

Summary

Using nested wiki pages in Gitlab CE throws a 500 error. I'm trying to view a child item of a parent as the navbar correct shows it however I cannot access it. Have attempted to reconfigure and update but it's still throwing the 500 error.

Steps to reproduce

Create a wiki with nested pages and attempt to view a nested page

What is the current bug behavior?

Throws a 500 error

What is the expected correct behavior?

The child page

Relevant logs and/or screenshots

Started GET "/[project]/application/wikis/parent/Child" for 192.168.1.XX at 2017-12-25 10:02:25 +0000
Processing by Projects::WikisController#show as HTML
  Parameters: {"namespace_id"=>"[project]", "project_id"=>"application", "id"=>"parent/Child"}
Completed 500 Internal Server Error in 26ms (ActiveRecord: 4.4ms)

ActionView::Template::Error (undefined method `author_name' for nil:NilClass):
    11:   .nav-text
    12:     %h2.wiki-page-title= @page.title.capitalize
    13:     %span.wiki-last-edit-by
    14:       = (_("Last edited by %{name}") % { name: "<strong>#{@page.last_version.author_name}</strong>" }).html_safe
    15:       #{time_ago_with_tooltip(@page.last_version.authored_date)}
    16:
    17:   .nav-controls
  app/views/projects/wikis/show.html.haml:14:in `_app_views_projects_wikis_show_html_haml__4299848408228882358_70095333937900'
  app/controllers/projects/wikis_controller.rb:18:in `show'
  lib/gitlab/i18n.rb:47:in `with_locale'
  lib/gitlab/i18n.rb:53:in `with_user_locale'
  app/controllers/application_controller.rb:324:in `set_locale'
  lib/gitlab/middleware/multipart.rb:93:in `call'
  lib/gitlab/request_profiler/middleware.rb:14:in `call'
  lib/gitlab/middleware/go.rb:18:in `call'
  lib/gitlab/etag_caching/middleware.rb:11:in `call'
  lib/gitlab/middleware/read_only.rb:31:in `call'
  lib/gitlab/request_context.rb:18:in `call'
  lib/gitlab/metrics/requests_rack_middleware.rb:27:in `call'

Results of GitLab environment info

GitLab 10.3.0