We have a mixed Exchange Server 2010 and 2003 environment. We all use Outlook 2007 (SP2).
Users that have been migrated to Exchange 2010 are experiencing the following problem.
1. Use creates a meeting in their personal calendar (not a public folder) and invites attendees.
2. The user "sits" on the unsent invitation for a while (say about 1 hour) - i.e. they leave the item open and unsent ... they get called away or get on the phone for example.
3. The user then sends the meeting and all attendees receive the meeting invite and are able to accept, decline, etc.
4. The meeting does not appear in the "organizer's" calendar
If the user creates the meeting, invites attendees and sends the meeting within a 10 minute interval, then the meeting does appear in the organizer's calendar.
This does not happen to users that are still on the Exchange 2003 server.
This does not happen to users on the Exchange 2010 server that are using Outlook 2010.