Every time I save an event, the 'Early Bird discount date' is reduced by one day. This also happens on the 'Cancel before date', but not on the Event dates. The event dates do not change.
So if I set the date to 2011-12-02 and then save it, when I open it again it will say 2011-12-01. If I save and open it again, it will say 2011-11-30 and so on.
This happens if the date is entered manually or by popup calendar, or even if I do not look at the Discount tab when I open and save the event. It always takes one day off the early bird discount date.
Local PC, Joomla time zone setting and server are all in same time zone.