Inconsistent syncing with Exchange

[skeltonr]

I have a user that carries a Droid X and a MAC Book Pro with Office 2011 installed. The user connects to a SBS 2008 utilizing Exchange 2007. Occasionally, the user experiences inconsistency between these components. For example the last situation, the user inputs two calendar entries on the Droid, later that day while talking to another user and viewing shared calendars from Outlook 2007, the user noticed that the entries were not on the user’s calendar.
While investigating, I discovered that these two entries where the only inconsistency for that entire month. Any new entries synced and were verified by the Droid and OWA. I had to recreate the original two entries on the Droid to get them to sync properly.
This same type of situation has happened with MAC and Outlook 2011 in the past. This user seems to be the only one experiencing syncing issues. There is another user that has a Droid and MAC Pro with Office 2011, but never experiences inconsistency.
I have checked the logs and made sure everything is up to date. At this level I don’t see any errors or warnings. I am looking for some advice on how to troubleshoot this issue or to see if anyone has a fix.
Any input is greatly appreciated
Sincerely
Skeltonr