I have the issue that during the last few days I haven't been able to drag-and-drop reschedule any posts for November. The days are all grayed out as they'd be history. Today, on 15.10.2012, the first white (current or future) date is 15.11.2012, a month in the future.
Other parts of the WordPress site function fine. Scheduled posts were published on the correct days and so forth. Only the calendar view of Editorial Calendar shows this anything wrong, and only in this way.