A 500 internal error occurs when viewing a particular wiki page, the following appears in the log:

Started GET "/redmine/projects/projName/wiki/SomeWikiPage" for  at Thu Sep 26 13:57:39 +1000 2013
Processing by WikiController#show as HTML
  Parameters: {"project_id"=>"projName", "id"=>"SomeWikiPage"}
  Current user: userName(id=3)
Completed 500 Internal Server Error in 19ms

NoMethodError (undefined method `current_version?' for nil:NilClass):
  app/controllers/wiki_controller.rb:96:in `show'

The error is 100% repeatable when viewing this particular page, although other wiki pages are rendered ok.
We believe it may have happened after deleting a revision on the wiki history page.
We tried to repeat it on the redmine demo site with no luck, although the demo site says it was running 2.3.1.devel.11915, we are using 2.3.3.stable.

Environment:
Redmine version 2.3.3.stable
Ruby version 1.8.7-p253 (2010-04-19) [i686-linux]
Rails version 3.2.13
Environment production
Database adapter Mysql2
Redmine plugins:
redmine_github_hook 0.2.0