Logged-in users switching between secure & non-secure pages see role-based blocks/views disappear/reappear

My site is set to make only certain pages secure. One of these is a view set to show in the main menu for users with certain roles. The login page is also secure. When any user logs in they see the link appear in the menu and have access to it, as normal. If however they then go to a non-secure page, the menu link disappears, along with any blocks set to show only to that role. They're still logged in, however, so if they manually go to the secure view they still get access to it and the menu link and blocks reappear. This is happening across all roles (except anonymous) and all browsers. I originally got this on the latest dev version and rolled back to the beta, but got the same results. I have cleared cache several times. In fact, originally I wasn't getting this problem when logged in as admin on Firefox so thought it was browser-based but after clearing cache the same thing is now also affecting the admin role on that and any browser.

Edit: just to confirm there are no roles ticked in the secure pages settings.