Missing events from Google Calendar

This is a well known Google limitation:

If you've imported calendar entries from another calendar system into Google Calendar, you may find that only the first occurrence of the event is synchronized, or - in some cases - the event may not be synchronized at all. Events which occur multiple times per month (for example "the first and last Monday of each month") cannot be accurately represented in the Microsoft Exchange ActiveSync protocol. Recurring events created within Google Calendar will sync correctly.
(source: Google)