I have create two new series appointments. One Starts bevor End of Saving Daylight Time, the second starts after 25. Oct.:
DTSTART;TZID=Europe/Berlin:20201023T100000
DTEND;TZID=Europe/Berlin:20201023T110000
RRULE:FREQ=WEEKLY;WKST=MO;UNTIL=20201120T225959Z;BYDAY=FR
DTSTAMP:20201112T204328Z
UID:@google.com
CREATED:20201112T204057Z
DESCRIPTION:
LAST-MODIFIED:20201112T204157Z
LOCATION:
SEQUENCE:0
STATUS:CONFIRMED
SUMMARY:SavingDaylightTime
TRANSP:OPAQUE
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20201030T100000
DTEND;TZID=Europe/Berlin:20201030T110000
RRULE:FREQ=WEEKLY;WKST=MO;UNTIL=20201120T225959Z;BYDAY=FR
DTSTAMP:20201112T204328Z
UID:@google.com
CREATED:20201112T204000Z
DESCRIPTION:
LAST-MODIFIED:20201112T204211Z
LOCATION:
SEQUENCE:0
STATUS:CONFIRMED
SUMMARY:AfterSavingDaylightTime
TRANSP:OPAQUE
END:VEVENT
END:VCALENDAR
Result: