CalDav: Time offsets do not sync correctly for events starting and ending in different time zones

I use gSyncit 64-bit for Microsoft Outlook v4.2.275.0 to synchronize Outlook 2010 (Version: 14.0.7177.500, 64-bit) to Nextcloud 11.0.1

When synchronizing an appointment (a transatlantic flight) set up in Outlook starting in a time zone -0500 GMT and ending (the next day) in a time zone +0100 GMT the time offsets are not correctly synchronized:

Departure: 27FEB, 21:15 (time zone -0500 GMT)

Arrival: 28FEB, 14:15 (time zone +0100 GMT)

Outlook correctly displays the starting time as 28FEB 03:15 as I’m in Europe.

Nextcloud incorrectly displays starting time as 28FEB 09:15 (which probably results from incorrectly assuming that the “28FEB 03:15” entry corresponds to the origin -0500 GMT time zone).

I contacted the gSyncit developer and he says:

"I checked the gSyncit source code and we do split the start/end time zone information when we submit the event to the CalDav server…

Based on the data you have provided….

The Outlook event shows the correct information …

DTEND;TZID=“W. Europe Standard Time”:20170228T141500
DTSTART;TZID=“SA Pacific Standard Time”:20170227T211500

gSyncit will map these time zones to…

OutlookTimeZone id=“W. Europe Standard Time” ical="Europe/Berlin"
OutlookTimeZone id=“SA Pacific Standard Time” ical=“America/Bogota”

But in nextCloud they appear as …

DTEND;TZID=America/Bogota:20170228T141500
DTSTART;TZID=America/Bogota:20170228T031500
"
Originating a test appointment in Nextcloud and transfering it to Outlook results in the mirrored effect. That is, it is displayed correctly in Nextcloud and incorrectly in Outlook (but differently: the appointment doesn’t seem to contain any time zone information).

Will appreciate any help on correcting this behavior

Thanks

-Daniel

For the records: CadDav Synchronizer (https://sourceforge.net/projects/outlookcaldavsynchronizer/) correctly deals with the described mapping of time zones. As stated in the excellent post https://nextcloud.com/blog/nextcloud-offers-caldav-synchronizer-for-outlook-users/ by jospoortvliet it might be because "What is also happening is that the synchronizer will take the idiosyncracies of our calendar and contacts apps into account."
It still hope to get a solution for gSyncit as I use it to sync ToDo tasks to Toodledo (https://www.toodledo.com).

Thanks
-Daniel