Issues with Google Calendar Export

[FredFronky]

I'm having an issue with the Google Calendar export feature.
When I attempt to export the generated timetable into a new Google calendar, parts of the timetable export, but other parts don't.
I tried exporting several times, and each time a different part exports, but never the complete timetable.
The three calendars in the screenshot below should all be the same.

Let me know if there's anything I can do to help.
Thanks

[FredFronky]

I found a workaround for this, which is reasonably painless.
Basically, just export the timetable several times into the same Google Calendar. This ensures that every event is created at least once. The problem is that most events will be created more than once. Either live with that, or remove duplicates using something like GCalToolkit (unfortunately expenisve software, but the free trial works quite well).
Let me know if anyone knows of an open source alternative that does the same thing.