random redirect loop with F5 in place

Great question. Here's what I understand. Some of the pages are secured, most are not. The initial request comes into the app server, which then redirects unauthenticated sessions to the single-sign on server. Once authenticated, the sessions is directed back at the app server. The current iRule prevents a loop here. However, the second loop is pure http and subsequent loops are inconsistent with the above (first) loop. When back at the app server the client can click a link the moves them to a page in a parallel folder on the app server. For about a dozen links, this throws the client into a loop. Clear as mud?