Same here! Entire business (60 users) uses Outlook for Mac 15.6 (latest supporting Mavericks 10.9 apparently!!) and appointment time zone are all mixed up! Seem to be only happening on recurring events however, because on single occurence event time zone
work correctly, but when people make recurring events, time zone are fu**** up!
I am working on different scenario and one observation is appear to be related with the system language. Time zones shown in Outlook for Mac 15.6 are completely different between the FRENCH version and ENGLISH version (we are in Canada BTW). People working
in french have a default time zone called (INDIANA, EAST (-5.00) and people in english have a default time zone called (USA/CANADA, EAST (-5.00). Both are -5.00 GST, but when people are sending invitation between a french and english computer, Outlook seem
mixed up between time zone.
Note than all hour business computer are in the right time zone no matter if they are english or french language. It's only Outlook for Mac 15 who look to be confused between time zones!
Hope Microsoft will work on that soon because at this point, Outlook for Mac 15 (O365) are an HORRIBLE client software for a business use... there's so many issues preventing a optimal work in business environment, what a shame!!!
I know it probably don't help on your case, but be aware someone else share your issue!!