Fruux is the calendar hosting service in question. The process I’ve used to reproduce this is as follows:
If trying to reproduce from another country/timezone the key point is to create an event across a daylight savings time switchover.
Here is the raw ICS version of the KOrganizer calendar:
BEGIN:VCALENDAR
VERSION:2.0
CALSCALE:GREGORIAN
PRODID:-//SabreDAV//SabreDAV 3.1.0-alpha2//EN
X-WR-CALNAME:KOrganizer
X-APPLE-CALENDAR-COLOR:#e6c800FF
BEGIN:VTIMEZONE
TZID:Europe/Dublin
BEGIN:STANDARD
TZNAME:IST
TZOFFSETFROM:+0000
TZOFFSETTO:+0100
DTSTART:19820328T010000
RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=3
END:STANDARD
BEGIN:STANDARD
TZNAME:IST
TZOFFSETFROM:+0000
TZOFFSETTO:+0100
DTSTART:19720319T020000
RRULE:FREQ=YEARLY;UNTIL=19810329T010000;COUNT=9;BYDAY=3SU;BYMONTH=3
RDATE;VALUE=DATE-TIME:19800316T020000
END:STANDARD
BEGIN:STANDARD
TZNAME:GMT
TZOFFSETFROM:+0100
TZOFFSETTO:+0000
DTSTART:19811025T020000
RRULE:FREQ=YEARLY;UNTIL=19891029T020000;COUNT=8;BYDAY=4SU;BYMONTH=10
END:STANDARD
BEGIN:STANDARD
TZNAME:GMT
TZOFFSETFROM:+0100
TZOFFSETTO:+0000
DTSTART:19901028T020000
RRULE:FREQ=YEARLY;UNTIL=19991031T020000;COUNT=9;BYDAY=4SU;BYMONTH=10
END:STANDARD
BEGIN:STANDARD
TZNAME:GMT
TZOFFSETFROM:+0100
TZOFFSETTO:+0000
DTSTART:20001029T020000
RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=10
END:STANDARD
BEGIN:STANDARD
TZNAME:GMT
TZOFFSETFROM:+0100
TZOFFSETTO:+0000
DTSTART:19721029T030000
RDATE;VALUE=DATE-TIME:19721029T030000
RDATE;VALUE=DATE-TIME:19731028T030000
RDATE;VALUE=DATE-TIME:19741027T030000
RDATE;VALUE=DATE-TIME:19751026T030000
RDATE;VALUE=DATE-TIME:19761024T030000
RDATE;VALUE=DATE-TIME:19771023T030000
RDATE;VALUE=DATE-TIME:19781029T030000
RDATE;VALUE=DATE-TIME:19791028T030000
RDATE;VALUE=DATE-TIME:19801026T030000
RDATE;VALUE=DATE-TIME:19881023T020000
RDATE;VALUE=DATE-TIME:19981025T020000
END:STANDARD
END:VTIMEZONE
BEGIN:VEVENT
DTSTAMP:20181024T122432Z
CREATED:20181024T122432Z
UID:5198c47c-5bd2-47f7-bbc3-021eacb163d0
LAST-MODIFIED:20181024T122432Z
SUMMARY:KOrganizer Test Event
DTSTART;TZID=Europe/Dublin:20181031T150000
DTEND;TZID=Europe/Dublin:20181031T160000
TRANSP:OPAQUE
END:VEVENT
END:VCALENDAR
And here is the ICS version of the DAVdroid calendar:
BEGIN:VCALENDAR
VERSION:2.0
CALSCALE:GREGORIAN
PRODID:-//SabreDAV//SabreDAV 3.1.0-alpha2//EN
X-WR-CALNAME:DAVdroid
X-APPLE-CALENDAR-COLOR:#e6c800FF
BEGIN:VTIMEZONE
TZID:Europe/Dublin
TZURL:http://tzurl.org/zoneinfo/Europe/Dublin
X-LIC-LOCATION:Europe/Dublin
BEGIN:DAYLIGHT
TZOFFSETFROM:+0000
TZOFFSETTO:+0100
TZNAME:IST
DTSTART:19810329T010000
RRULE:FREQ=YEARLY;BYMONTH=3;BYDAY=-1SU
END:DAYLIGHT
BEGIN:DAYLIGHT
TZOFFSETFROM:-002521
TZOFFSETTO:+003439
TZNAME:IST
DTSTART:19160521T020000
RDATE:19160521T020000
END:DAYLIGHT
BEGIN:DAYLIGHT
TZOFFSETFROM:+0000
TZOFFSETTO:+0100
TZNAME:BST
DTSTART:19170408T020000
RDATE:19170408T020000
RDATE:19180324T020000
RDATE:19190330T020000
RDATE:19200328T020000
RDATE:19210403T020000
END:DAYLIGHT
BEGIN:DAYLIGHT
TZOFFSETFROM:+0000
TZOFFSETTO:+0100
TZNAME:IST
DTSTART:19220326T020000
RDATE:19220326T020000
RDATE:19230422T020000
RDATE:19240413T020000
RDATE:19250419T020000
RDATE:19260418T020000
RDATE:19270410T020000
RDATE:19280422T020000
RDATE:19290421T020000
RDATE:19300413T020000
RDATE:19310419T020000
RDATE:19320417T020000
RDATE:19330409T020000
RDATE:19340422T020000
RDATE:19350414T020000
RDATE:19360419T020000
RDATE:19370418T020000
RDATE:19380410T020000
RDATE:19390416T020000
RDATE:19400225T020000
RDATE:19470316T020000
RDATE:19480418T020000
RDATE:19490403T020000
RDATE:19500416T020000
RDATE:19510415T020000
RDATE:19520420T020000
RDATE:19530419T020000
RDATE:19540411T020000
RDATE:19550417T020000
RDATE:19560422T020000
RDATE:19570414T020000
RDATE:19580420T020000
RDATE:19590419T020000
RDATE:19600410T020000
RDATE:19610326T020000
RDATE:19620325T020000
RDATE:19630331T020000
RDATE:19640322T020000
RDATE:19650321T020000
RDATE:19660320T020000
RDATE:19670319T020000
RDATE:19680218T020000
RDATE:19720319T020000
RDATE:19730318T020000
RDATE:19740317T020000
RDATE:19750316T020000
RDATE:19760321T020000
RDATE:19770320T020000
RDATE:19780319T020000
RDATE:19790318T020000
RDATE:19800316T020000
END:DAYLIGHT
BEGIN:STANDARD
TZOFFSETFROM:+0100
TZOFFSETTO:+0000
TZNAME:GMT
DTSTART:19961027T020000
RRULE:FREQ=YEARLY;BYMONTH=10;BYDAY=-1SU
END:STANDARD
BEGIN:STANDARD
TZOFFSETFROM:-0025
TZOFFSETTO:-002521
TZNAME:DMT
DTSTART:18800802T000000
RDATE:18800802T000000
END:STANDARD
BEGIN:STANDARD
TZOFFSETFROM:+003439
TZOFFSETTO:+0000
TZNAME:GMT
DTSTART:19161001T030000
RDATE:19161001T030000
END:STANDARD
BEGIN:STANDARD
TZOFFSETFROM:+0100
TZOFFSETTO:+0000
TZNAME:GMT
DTSTART:19170917T030000
RDATE:19170917T030000
RDATE:19180930T030000
RDATE:19190929T030000
RDATE:19201025T030000
RDATE:19211003T030000
RDATE:19221008T030000
RDATE:19230916T030000
RDATE:19240921T030000
RDATE:19251004T030000
RDATE:19261003T030000
RDATE:19271002T030000
RDATE:19281007T030000
RDATE:19291006T030000
RDATE:19301005T030000
RDATE:19311004T030000
RDATE:19321002T030000
RDATE:19331008T030000
RDATE:19341007T030000
RDATE:19351006T030000
RDATE:19361004T030000
RDATE:19371003T030000
RDATE:19381002T030000
RDATE:19391119T030000
RDATE:19461006T030000
RDATE:19471102T030000
RDATE:19481031T030000
RDATE:19491030T030000
RDATE:19501022T030000
RDATE:19511021T030000
RDATE:19521026T030000
RDATE:19531004T030000
RDATE:19541003T030000
RDATE:19551002T030000
RDATE:19561007T030000
RDATE:19571006T030000
RDATE:19581005T030000
RDATE:19591004T030000
RDATE:19601002T030000
RDATE:19611029T030000
RDATE:19621028T030000
RDATE:19631027T030000
RDATE:19641025T030000
RDATE:19651024T030000
RDATE:19661023T030000
RDATE:19671029T030000
RDATE:19711031T030000
RDATE:19721029T030000
RDATE:19731028T030000
RDATE:19741027T030000
RDATE:19751026T030000
RDATE:19761024T030000
RDATE:19771023T030000
RDATE:19781029T030000
RDATE:19791028T030000
RDATE:19801026T030000
RDATE:19811025T020000
RDATE:19821024T020000
RDATE:19831023T020000
RDATE:19841028T020000
RDATE:19851027T020000
RDATE:19861026T020000
RDATE:19871025T020000
RDATE:19881023T020000
RDATE:19891029T020000
RDATE:19901028T020000
RDATE:19911027T020000
RDATE:19921025T020000
RDATE:19931024T020000
RDATE:19941023T020000
RDATE:19951022T020000
END:STANDARD
BEGIN:STANDARD
TZOFFSETFROM:+0000
TZOFFSETTO:+0000
TZNAME:GMT
DTSTART:19211206T000000
RDATE:19211206T000000
RDATE:19960101T000000
END:STANDARD
BEGIN:STANDARD
TZOFFSETFROM:+0100
TZOFFSETTO:+0100
TZNAME:IST
DTSTART:19681026T230000
RDATE:19681026T230000
END:STANDARD
END:VTIMEZONE
BEGIN:VEVENT
DTSTAMP:20181024T122609Z
UID:3bd064c2-b586-4d1d-ae08-f2f2797b5f08
SUMMARY:DAVdroid Test Event
DTSTART;TZID=Europe/Dublin:20181031T150000
DTEND;TZID=Europe/Dublin:20181031T160000
CLASS:PRIVATE
STATUS:CONFIRMED
END:VEVENT
END:VCALENDAR
Both are exactly as downloaded by Fruux except for the removal of the X-FRUUX-URL field from both events. The obvious difference is in the VTIMEZONE definition, but given Fruux also reads both correctly I’m unsure whether the issue lies in the libraries used by DAVdroid for parsing ICS or elsewhere?
Any help appreciated.
Hello,
Thanks for your verbose report. However, I can’t reproduce this problem with the current DAVdroid version, Android 9.0 (plain emulator image) and Google Calendar 5.7 as calendar app, which shows your KOrganizer event like this:
Please provide steps to reproduce your DAVdroid debug info (DAVdroid / Settings / Debug info) which contains your DAVdroid version and other important information; and verbose DAVdroid logs while it downloads the event as described in [READ BEFORE POSTING] What’s required to diagnose a problem.
@rfc2822 apologies, I forgot to include version information. I’m running:
Although while checking that I’ve just realised that the Oreo 8.1 update has finally been released for my phone, so I’ll install that and check tonight too. I’ll also enable logging to an external file and get you that info in the process. 
