Yep, I've noticed it before on the dashboard and add-ons webpage (where it shows that error and doesn't log me out until I refresh the page as you say)
However, of late, it shows that error even when logging out from the forum home page or any topic/thread I'd be viewing.
So it continues to log me out at first attempt as has always happened (only difference being that in addition, it now shows that error anyway).
Not a biggie though - just some observation.