It looks like this bug has resurfaced, this time under the iPhone's support for Phoenix, Arizona (MST, no daylight savings time).
The problem? If you enable Time Zone Support for Phoenix, AZ in the iPhone Calendar settings, any event you create will be marked for Time Zone: Africa/Ouagadougou in iCal. This is a rather annoying bug for us Phoenicians because if I turn off Time Zone Support in the iPhone, all of my events appear 1 hour earlier, or if I keep it on, it's displayed correctly in the iPhone and Web client, but in iCal, it's shown 5 hours earlier.
It doesn't seem like a complex fix, but again, we Network Edition customers are at the mercy of the Zimbra developers to resolve this bug. We can't say how happy we are to move from Exchange, but we also need time zones to be functional for us!