As I understand it, this is clearly a Google Calendar problem. We could introduce ugly and cumbersome workarounds (like faking a new main event with RDATEs for all instances) for this; but these events as given are not valid. The same behavior would at the latest with CalDAV and r/w calendars cause problems and unsyncable events. Also, I have never seen it from any other client or server.
Do you know whether other iCalendar clients (like Thunderbird, Evolution, Outlook…) can understand these events?
Do you know where to report Google Calendar problems?