I discovered this today, and thought I'd share the experience.
I have a report named "Yesterday's Calls" with the filter set for date created that is on a schedule for each work day.
One of the sales managers is in a time zone three hours ahead of a sales rep that was recording their day's calls in Sugar after 9:00 PM. The calls were not appearing on the manager's report.
The solution was to change the filter to "start date = yesterday" instead of using the date created.
In hindsight, this probably should have been obvious :-)
