Agents and client are 8.0.2HP2 running on Windows Server 2003 Standard and Windows XP.

Try this:
1. Create a Posted Appointment using whatever defaults you have and just put whatever you like in the Subject line. Close and save it. The appointment appears on your calendar.
2. Open the same Posted Appointment and notice that the Subject contains whatever you typed.
3. Now, add an email address to the Subject line -, or whatever. Close and save the appointment.
4. Open the appointment. On my PC, and that of the person who found this and brought it to my attention, the Subject line is now empty. The rest of the appointment is there, just the Subject has been deleted. Yes, it appears when you look at the Calendar view, but in the actual appointment the Subject is blank.
5. If you enter new stuff in the Subject line the previous stuff deletes.

You can also get the same outcome when using a standard Appointment with an email address in the subject...
...if you just open the standard Appointment (double-click it in your calendar) the Subject displays properly.
...if you Resend the standard Appointment (right-click...Resend...) the Subject is blank. Enter new text into the subject and it will erase whatever was already there. Just resend it with the now blank Subject and the existing subject will remain.

So my question is...what's up with that?