It is important to understand that the Meeting Maker servlet stores PIM dates/times in GMT. In certain situations this can alter dates/times associated with calendar events or tasks and in turn the way those events or tasks are processed.
One such scenario is as follows:
A monthly recurring meeting that is scheduled on the 28th may result in the GMT date/time of the event occurring on the 29th.
This could occur if the recurring appointment on the 28th of each month is scheduled during the GMT shadow. The GMT shadow, for time zones west of GMT, is defined as the hours of the day after GMT midnight (for example, after 7:00 p.m. EST).
Since Meeting Maker does not support monthly recurring events occurring on the 29th (a day not all months have), an event in this scenario may NOT be added to the calendar. (See Knowledge Base article #165.)
What is GMT and why is it used? http://wwp.greenwichmeantime.com/what-is-gmt.htm