@rfc2822 said in Creating/editing a recurring event makes it an all-day event.:

Trying the same thing in Thunderbird/Lightning looks more reasonable:

Why?

Yeah, I was confused by the whole definition of the timezone being included in the event (1916, 1917 etc.), my mistake.

Indeed looking at what is returned from the server after sync is something like this:

BEGIN:VCALENDAR PRODID:-//Alt-N Technologies Ltd//MDaemon 17.5.2 VERSION:2.0 METHOD:PUBLISH BEGIN:VEVENT UID:af4a2cd0-7ccd-4661-86c8-5bcc7d56ba78 SEQUENCE:0 DTSTAMP:20180307T214530Z SUMMARY:Schrauwem PRIORITY:5 DTSTART;VALUE=DATE:20180110 DTEND;VALUE=DATE:20180111 TRANSP:OPAQUE RRULE:FREQ=WEEKLY;COUNT=10;BYDAY=WE BEGIN:VALARM ACTION:DISPLAY TRIGGER;VALUE=DURATION:-PT10M END:VALARM END:VEVENT END:VCALENDAR

Clearly, the time is missing.
I’ll open a ticket with the server vendor.

Cheers.