Thanks for the response on the OAB generation and dgoldman's blog, but I'd already seen that. That is a manual fix for a process that I would think would be autocorrecting in a redundant scenario. We did use that to get things working, but I'd consider it a workaround, not a solution. In a highly available scenarion, that should fix itself.
Another suggestion, probably a bug. We've noticed that if someone creates a new appointment and unchecks the reminder box (so no 15 minute reminder should be given to recipients), the box is re-checked when the recipients get the meeting (regardless of their default settings).
Not sure if there's already a fix in the owrks for this, but it's generating some support calls from those who hate reminders. FYI, we are still running OL2003 clients.