The print header function should set cache control header or callers should conditionally set to prevent caching. Something like, 'Cache-Control: no-cache, no-store, must-revalidate, proxy-revalidate', should be sufficient.

This is an issue on the bug_report_advanced_page redirecting to the project selection page and getting into a loop due to the caching (via proxy) of the redirect.

GET /bug_report_advanced_page.php
<- 302 to /login_select_proj_page.php (cacheable)
GET /login_select_proj_page.php
<- 200 (not cacheable)
POST /set_project.php
<- 302 to /bug_report_advanced_page.php (not cacheable)
GET /bug_report_advanced_page.php
<- 302 to /login_select_proj_page.php (cacheable) loop