Upon logging in, sometimes our users encounter a 404 dead link on the front page.
Navigation of the site is otherwise not impaired, but they are not sure why they see it sometimes.
Logging out and logging back in sometimes reproduces this issue, but sometimes it does not.
Looking in the logs, I found this line which seems to show the issue:
2012-12-07 12:12:28,104 DEBUG http-bio-7990-exec-7 hiddenuser 732x1449x1 12eb9tg some.ip.address,127.0.0.1 GET /mvc/error404 HTTP/1.0 c.a.s.i.web.ErrorPageController Page not found attempting to access /secure/Dashboard.jspa