iCal invite appears at wrong older date
When you receive a calendar invite in Apple Mail and click on the attached file, it opens iCal and either disappears or appears at an incorrect older or wrong date. The invite sometimes seems to link or is associated with an old date or old event in the past. This happens with Mac OS 10.8 Mountain Lion.
A simple workaround is to drag the .ics file attached to the email directly to iCal, either on top of the application icon or into its window.