Incorrect multi-day collation

[Sec42]

If there are two consecutive lines with the same event, it appears that they are converted into a multi-day event, even if the days are not consecutive. This can (currently) be seen e.g. with the hackfriday on May 1st and May 8th:

BEGIN:VEVENT
SUMMARY:hackfriday
DTSTART;VALUE=DATE:20200501
DTEND;VALUE=DATE:20200503
UID:wikical1.5.hackfriday.19.30@api.muc.ccc.de
DESCRIPTION:Public
LOCATION:Hauptraum
URL:https://wiki.muc.ccc.de/hackfriday
END:VEVENT