officenewbie,

Through all of my tools available to me, I have been unable to replicate this on any VM running Outlook2007.

If you are using an exchange service it is possible to clean free busy information. Not sure if this resolve your issue but it is worth a shot:

To run Outlook with a command line switch, use the following steps:

Windows XP:

• Click Start.
• Click Run.
• Enter the following in the Run dialog box (with quotations):
  "c:\program files\microsoft office\office12\Outlook.exe" /cleanfreebusy
• Click OK.

Hope this helps.