Links to attachments rendered unresolved when viewing historic versions of pages

Up until 3.5, when viewing old version of pages, the links to pages attachments (i.e. defined as [^attachment.dat]) were rendered properly.

However, in 4.x when you view an old version of a page, the link is grayed out (i.e. undefined).

This causes serious problems with Ad hoc Workflows as it relies on historic versions of pages to handle published versions of pages.