Wrong display of calendar entries with different timezone for start and stop date

Timezone of stop date is ignored for ics files and caldac calendars.
The attached example has a during of 7 hours. It gets imported correctly with evolution.
However, it looks like an event with a duration of one hour in the calendar. Thunderbird displays the event correctly (as my iPhone).

Import creates error message if stop time in local timezone is 'before' start time in specified timezone (see second example). Event is not displayed in the regular calender view but can be seen in the list view.

When I open the entry, I can only choose a timezone for the entire event, i.e., not for start and stop date separately.

Expected behavior:
- correct display of length of event in the calendar view
- separate entry fields for timezones for start and stop date (cf. Thunderbird - Lightning)

Example 1:
BEGIN:VCALENDAR
PRODID:-//Mozilla.org/NONSGML Mozilla Calendar V1.1//EN
VERSION:2.0
BEGIN:VEVENT
CREATED:20180610T131500Z
LAST-MODIFIED:20180610T131418Z
DTSTAMP:20180610T131418Z
UID:20180610_JK_Test1
SUMMARY:New Test Appointment
DTSTART;TZID=Europe/Berlin:20180610T130000
DTEND;TZID=America/New_York:20180610T140000
END:VEVENT
END:VCALENDAR

Example 2:
BEGIN:VCALENDAR
PRODID:-//Mozilla.org/NONSGML Mozilla Calendar V1.1//EN
VERSION:2.0
BEGIN:VEVENT
CREATED:20180610T131500Z
LAST-MODIFIED:20180610T131418Z
DTSTAMP:20180610T131418Z
UID:20180610_JK_Test2
SUMMARY:Short Test Appointment
DTSTART;TZID=Europe/Berlin:20180610T130000
DTEND;TZID=America/New_York:20180610T110000
END:VEVENT
END:VCALENDAR

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: evolution 3.28.1-2
ProcVersionSignature: Ubuntu 4.15.0-22.24-generic 4.15.17
Uname: Linux 4.15.0-22-generic x86_64
NonfreeKernelModules: wl
ApportVersion: 2.20.9-0ubuntu7.2
Architecture: amd64
CurrentDesktop: ubuntu:GNOME
Date: Sun Jun 10 15:41:39 2018
EcryptfsInUse: Yes
InstallationDate: Installed on 2018-04-05 (65 days ago)
InstallationMedia: Ubuntu 18.04 LTS "Bionic Beaver" - Alpha amd64 (20180403)
SourcePackage: evolution
UpgradeStatus: No upgrade log present (probably fresh install)