Changing EXDATE between start and end date fails to update the calendar

Question

I am sending emails to Outlook with ICS attachments. In the ICS file, I am declaring a recurring series with EXDATEs and calendar seems to be updated correctly.

For an event with,

EXDATE:20221124T140000Z,20221125T140000Z   
RRULE:FREQ=DAILY;UNTIL=20221126T140000Z  
DTSTART:20221123T140000Z  
DTEND:20221123T170000Z    

days are marked as 23rd Nov and 26th Nov, which is correct.

When I try to update this event to days 23rd, 24th and 26th Nov, I am sending another email with

EXDATE:20221125T140000Z   

but the calendar is not updated with dates. I confirmed the calendar updates other details like event summary or description but fails to update the EXDATE if the date is between the start and end date. Appending or removing an event from the start or end also updates the dates correctly.

Why I am trying to do this?

I am trying to send calendar invites for events that do not have pattern but still behave as a series. To do that I am creating a daily recurring event starting from the first event and ending on the last one, marking the days without events as EXDATEs. I am also open to suggestions if there is a better way to do this in calendars. 

Initial calendar invite

BEGIN:VEVENT   
DTSTAMP:20221121T155658Z   
LAST-MODIFIED:20221121T155658Z   
CREATED:20221121T114608Z   
SEQUENCE:15050   
EXDATE:20221124T140000Z,20221125T140000Z   
RRULE:FREQ=DAILY;UNTIL=20221126T140000Z   
DTSTART:20221123T140000Z   
DTEND:20221123T170000Z   
UID:1606456106451638  
SUMMARY:Test event  
URL:   
DESCRIPTION:   
CLASS:PUBLIC   
STATUS:CONFIRMED   
END:VEVENT  

Update invite

BEGIN:VEVENT   
DTSTAMP:20221121T160245Z   
LAST-MODIFIED:20221121T160245Z   
CREATED:20221121T114608Z   
SEQUENCE:15397   
EXDATE:20221125T140000Z   
RRULE:FREQ=DAILY;UNTIL=20221126T140000Z   
DTSTART:20221123T140000Z   
DTEND:20221123T170000Z   
UID:1606456106451638  
SUMMARY:Test event  
URL:   
DESCRIPTION:   
CLASS:PUBLIC   
STATUS:CONFIRMED   
END:VEVENT

Answer 1

As a workaround you can change the start or end time of the original event that defines the schedule (e.g. add one minute to the end time). This forces Outlook/Exchange to refresh all the occurrences and the changes become visible.