As we transition to the new Hyland Community, some post links may be temporarily disrupted as we finalize redirects. We apologize for the inconvenience and are working to resolve this as quickly as possible. Details.
One additional thing, when I try linking to the asset outside of the Wiki or Discussion, using the full link (http://serverort/proxy/alfresco-feed/api/node/content/workspace/SpacesStore/3573af44-856b-4b64-8b15-68e2488da0d4/HLArchitecture.pdf) it works perfectly. It's the fact that the WSYIWYG editor within Alfresco Share keeps rewriting the URL that seems to be the issue.
I think this is fixed now - should be in 3.2r