Comment 1 for bug 1724915

More info: the issue appears to require having multiple tabs open. A single tab polls at slightly longer than the auth timeout, so it normally attempts to retrieve sessions after they have expired, allowing the log out to proceed. With multiple tabs, though, action in either tab extends the auth session, causing the polling to get out of sync.

We could resolve this by moving the polling into a shared worker, but I prefer the API change because avoiding session-extension when polling seems like a good thing to do anyway. Plus, it could be useful in other contexts.