Pretty URL's seem to go AWOL occasionally...

Under some conditions, I still get URLS like http://jira.atlassian.com/secure/ViewIssue.jspa?key=JRA-2555 from search results - rather than http://jira.atlassian.com/browse/JRA-2555.

I say some conditions - this is because I cant repeatably get this behaviour. It seems that this comes and goes....