Odd Calendar Behavior

[brendan]

I have one user who; if using Zimbra Desktop the calendar displays correctly.
if using the Web interface the mini calendar shows BOLD to indicate appointments and hovering shows them, but the calendar does not show the appointments, right clicking and selecting view in separate window does show all appointments. CalDAV on iPhone working, CalDAV on Macbook indicates that the calendar does not exist. Zimbra Admin suggests he hasn't logged in since Sep.9, 2010 although he has accessed his account via Zimbra Desktop and via the Web.
I am confused.