icloud deleting events?

Has anyone else had trouble with appointments disappearing mysteriously off of your calendars? Any idea what could be going on?

Up until tonight I kept thinking possibly it might be "User Error" and that maybe I had just not entered an appointment when I found it missing. However, tonight I found one missing that I know for sure was scheduled and had been showing up in my calendars correctly for weeks. But tonight (2 days before the appointment) I go to check the time and POOF!! the appointment has vanished - no longer exists. So I am now extremely suspicious that this has been happening all along.

In case it is of use:

• I never used Mobile Me.
• This is effecting both my
  • iPhone 4, iOS 5.0.1, Verizon Wireless
  • MacBook Pro, Mac OS X (10.7.2)
• I now use WeekCal but I think this was also happening when I was just using the native iPhone calendar app too. (But am not entirely sure and am contacting WeekCal support too. And, I do not sync with a Yahoo calendar which is a known issue with WeekCal.)
• Prior to using iCloud I just synced using the cable straight to my computer and syncing with iTunes.
• I have multiple calendars and the issue seems to be occuring on more than one calendar.
• I do not "share" calendars with anyone.

Ps. If there is an Admin reading this - it seems pretty silly in the iCloud section you are splitting this out into iPhone, Mac, etc. iCloud connects all of our Apple products. If we are having problems with iCloud by its very nature we must be having issues on more than one product!

TIA!