I can reproduce the problem. The (a) problematic event is
This is an event without end (no
RRULE), and it seems that the existence of
EXDATE in such events can’t be processed by the Android calendar provider, which sends:
icsx5 : Found VEVENT: email@example.com
icsx5 : firstname.lastname@example.org not in local calendar, adding
RecurrenceProcessor: DateException with r=FREQ=MONTHLY;WKST=MO;BYDAY=3SU rangeStart=135390560256 rangeEnd=9223372036854775807
CalendarProvider2: Could not calculate last date.
CalendarProvider2: com.android.calendarcommon2.DateException: No range end provided for a recurrence that has no UNTIL or COUNT.
CalendarProvider2: at com.android.calendarcommon2.RecurrenceProcessor.expand(RecurrenceProcessor.java:768)
CalendarProvider2: at com.android.calendarcommon2.RecurrenceProcessor.expand(RecurrenceProcessor.java:663)
So, it seems that such events are not supported by Android.