I've been using iCal (now called Calendar.app) to view my Google Calendar calendars for a long time and generally haven't had a problem. However, in the last few weeks or months I've noticed that when I hit the "Snooze" button on iCal alerts, they never come back again like you would expect.
This definitely didn't used to be a problem but I don't know what changed. I've noticed the problem on both Lion and Mountain Lion.
I found this link to another user having what seems to be the same problem, but there are no responses: https://discussions.apple.com/thread/3372462?start=0&tstart=0
Any ideas why Snooze stopped working in my iCal alerts?