Samuel, I had one of our developers take a look and sure enough we logged this bug:
I’m not sure why, but sometimes Google Calendar responds with iCal data but excludes the BEGIN:VCALENDAR line. When that line is missing, the entire file gets skipped. If END:VCALENDAR is detected, let’s auto-insert BEGIN:VCALENDAR at the top of the file.
Thanks a lot for helping us discover (and hopefully soon fix) this issue.
I’ll mark this ticket as Pending Fix, which means this thread should receive a reply once the applicable fix has been released. I cannot guarantee when it will be fixed as it’s in the development team’s hands now. They need to assign it, code it, test it, and schedule it for release.
I apologize for this issue and appreciate your understanding and patience.