[Evolution] DTSTART differs

[Ralph Plawetzki <ralph purejava org>]

Dear list,

I've set up calendarserver.org as a calendars and contacts back-end for
evolution.
Saving a similar appointment on two clients with the same start-times
leads to appointments with different start-times.

Client 1
Arch linux with evolution 3.26.4-2
[user@six ~]$ timedatectl
                      Local time: Mo 2018-02-05 16:45:41 CET
                  Universal time: Mo 2018-02-05 15:45:41 UTC
                        RTC time: Mo 2018-02-05 15:45:41
                       Time zone: Europe/Berlin (CET, +0100)
       System clock synchronized: yes
systemd-timesyncd.service active: yes
                 RTC in local TZ: no
[user@six ~]$

Client 2
Ubuntu 17.10 with evolution 3.26.1-1
Time on the system is CET Europe/Berlin as well.

Both evolutions state to use the system time that is Europ/Berlin.

calendarserver itself does not have a time zone set as a default.

Problem:
When creating a new appointment on client 1 for 10:50 in evolution,
evolution saves it as 09:50
DTSTART;TZID=/freeassociation.sourceforge.net/Europe/Berlin:20180208T09500
 0
DTEND;TZID=/freeassociation.sourceforge.net/Europe/Berlin:20180208T100000

When creating a new appointment on client 2 for 10:50 in evolution,
evolution saves it as 10:50, which is correct.
DTSTART:20180208T095000Z
DTEND:20180208T100000Z

The evolution installations are the same, without any changed to the
config. Before setting up Ubuntu and testing on Ubuntu, I thought this
is a evolution bug, as iOS and macOS clients save appointments with the
correct start time.

So this seems to be a config issue, but I do not know what to change on
client 1 to solve the problem.

Any help would be appreciated.

Thanks.

Kind regards,
Ralph