Hello,
We have noticed that after import of .ical file a date for the all-day event is different than a real date of an event.
For instance, when we set event for 8/04/2018 .ical file contain DTEND and DTSTART like below.
BEGIN:VCALENDAR
VERSION:2.0
….
BEGIN:VEVENT
DTEND:20180407
UID:5a71924558e33
DTSTAMP:20180131T095413Z
……
DTSTART:20180407
RDATE:20180408T000000Z;
END:VEVENT
END:VCALENDAR