Recently "rememberme" is broken again

This is recent: since the last few days or so.
I find I am frequently logged out, without even closing the browser. Context:

1. Browser (Fx3) is set to accept permanent cookies for identi.ca
2. When I noticed the problem, I noted I had a '''permanent''' 'rememberme' cookie, and a '''temporary''' PHPSESSID cookie.
3. Tried clearing all cookies and re-login (making sure to check 'remember me'. Result: no 'rememberme' cookie anymore, only a (still temporary) PHPSESSID cookie

In spite of at least having a cookie that should last as long as the browser session, on coming back after a while and reloading the page, I'm just logged out again.

I "feels" like a problem with PHP's session garbage collector: as if it's removing sessions already while the browser session (cookie) hasn't expired yet. Let alone the apparently disappeared 'rememberme' (not even a cookie!).

@jarel confirmed today having the same problem.

(blurb in the footer says we're still on 0.5)