Org-mode version 9.2.2, Emacs 26.1, Windows 10

To reproduce:

Create a file "Test.org", with only one entry:

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* TODO Do this on the second Monday every month
   SCHEDULED: <%%(diary-float t 1 2) 19:00-20:30>
   :PROPERTIES:
   :ID:       5eb2262f-d7a4-4c10-8765-e1906a1cf276
   :END:

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Run this in the buffer of this above file:

M-x org-icalendar-export-to-ics

Check the output file "Test.ics", and you will see something like below, 
which obviously is wrong (I highlighted the wrong part).

BTW: regular org-agenda still works correctly with this entry (the TODO 
shows up correct at the right date)

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BEGIN:VCALENDAR
VERSION:2.0
X-WR-CALNAME:Test
PRODID:-////Emacs with Org mode//EN
X-WR-TIMEZONE:America/New_York
X-WR-CALDESC:
CALSCALE:GREGORIAN
BEGIN:VTODO

UID:TODO-5eb2262f-d7a4-4c10-8765-e1906a1cf276

DTSTAMP:20190326T141906Z

*DTSTART:20190326T101900*

SUMMARY:Do this on the second Monday every month

CATEGORIES:Test

SEQUENCE:1

PRIORITY:13

STATUS:NEEDS-ACTION

END:VTODO
END:VCALENDAR

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