Windows Live Calendar got an bug fix update on the following issues:  

Syncing Calendar: You’ll no longer see errors resulting from a high CPU usage for the couple of minutes after the calendar sync.  Also, you'll also see fewer error messages in general - we fixed some issues with checking for new calendar updates and meeting requests.  
Shared Calendars: We’ve fixed some of the rules for settings – so now, when you change the calendar settings for a shared calendar, it is updated for all of the other participants.