Google Calendar generated ics files displayed in Orage have an extra day in all-day-events. I opened up the ics file and understood why. Google Calendar, Sunbird and others assume that all-day-events start at (e.g.) 00:00 the 14th and end at 00:00 the 15th. So the VEVENT looks like this: ... DTSTART;VALUE=DATE:20110814 DTEND;VALUE=DATE:20110815 ... But Orage reads this as a two-day event! Which makes these kind of events to have an extra day. So, what I'm trying to say is that it would be nice if Orage would be compliant with these ics files!
yep, looks like a bug.
Fixed in 4.8.1.13 available in GIT.
Fix in 4.8.2