Apple iCal shifts dates of event repeats in calendar feed

I have a repeating event in my event calendar occurring on Thurs, Fri, and Sat for a number of weeks. It's displayed properly in my Drupal site's calendar. I've updated Calendar to 6.x-2.x-dev, and Date to 6.x-2.8+16-dev.

I've subscribed my Mac iCal calendar to the site's calendar feed, and the events for Thursday and Friday of the first week appear on the proper dates in my iCal display. However, there's no Saturday event shown that week, and the repeats in all the subsequent weeks are shifted one day early; they display there as Weds, Thurs, Fri events, with the dates on which they are being shown. (Even though when I click on one of the displayed events in my iCal calendar it says:

repeat Custom...
Every week on Thursday, Friday and Saturday

The relevant bit of the .ics file reads:

BEGIN:VEVENT
UID:calendar.19358.field_neweventdate.0.17
SUMMARY:Enchanted April
DTSTAMP:20120311T120234Z
DTSTART:20120316T030000Z
DTEND:20120316T044500Z
RRULE:FREQ=WEEKLY;INTERVAL=1;BYDAY=TH,FR,SA;UNTIL=20120409T065959Z;WKST=SU
URL;VALUE=URI:http://olyblog.net/enchanted-april
END:VEVENT

(My iCal calendar does start the week on Sunday, if you were wondering.) Apparently, this has something to do with the RRULE. I have tried setting FREQ to DAILY. That also works in the Drupal calendar, and fails the same way in Apple iCal.