Events from Asia/Ho_Chi_Minh timezone always imported at 23:00

[squatica]

I have this event:

BEGIN:VCALENDAR
VERSION:2.0
CALSCALE:GREGORIAN
PRODID:-Vivaldi Calendar V1.0//EN
DTSTAMP:20220810T045750Z
BEGIN:VTIMEZONE
TZID:Asia/Ho_Chi_Minh
BEGIN:DAYLIGHT
DTSTART:19750612T230000
TZNAME:+07
TZOFFSETFROM:+0800
TZOFFSETTO:+0700
END:DAYLIGHT
END:VTIMEZONE
BEGIN:VEVENT
UID:95a04035-ff01-4d11-8659-80ab593253f7
DTSTART;TZID=Asia/Ho_Chi_Minh:20220819T160000
DTEND;TZID=Asia/Ho_Chi_Minh:20220819T170000
DTSTAMP;VALUE=DATE-TIME:20220810T045750Z
RRULE:FREQ=WEEKLY;INTERVAL=1;BYDAY=FR
SEQUENCE:1
SUMMARY:test event
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:
TRIGGER:-PT5M
END:VALARM
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:test event
TRIGGER:-PT30M
END:VALARM
END:VEVENT
END:VCALENDAR

Ical validator says it's valid. When I sync this with syncthing to my phone, it gets imported at 20220819T230000, but it should be at 20220819T160000 (two different android calendar apps see it at 23:00, so I assume it's a problem with DecSyncCC). It looks like the timezone daylight savings definition gets in the way.