Recurring event first instance not matching rrule

[KrisLau]

Kind of a weird problem but several of my recurring events seem to be acting strange. So for example, I created a MWF 6:30 - 7:30am recurring event with a dtstart of today(Tuesday) so the first instance should be tomorrow (Wednesday). But in generated ics file it is seems to be including today. Left is the first occurrence generated by the jakubroztocil/rrule package and the right is the generated iCal being used in outlook:

RRule used:

DTSTART:20220329T183000Z
RRULE:FREQ=WEEKLY;INTERVAL=1;BYDAY=MO,WE,FR;UNTIL=20220930T202400Z

Behaviour is also replicated when importing the ICS file into Google Calendars. Actual ICS file used in the screenshot: calendar.txt

I have an idea for a "fix" of sorts where I could just call rrule.all()[0] to get the first occurrence and use that as the start date but that seems extremely hacky hahah. Is this expected behavior with those rules or am I doing something wrong?

EDIT: Looks like there is a very old open issue on rrule (jkbrzt/rrule#84) that states that it doesn't comply with the official protocol. However, I am unsure how I would set a non inclusive (doesn't include DTSTART unless it actually matches rrule) DTSTART?

[sebbo2002]

No, you are doing everything right so far. There is currently no way to use start and end only as bounds for the rrules. For this, ical-generator would have to be able to parse and interpret these rules again, so I left that out explicitly (ical-generator allows not only to specify a rrule object, but also to pass a string, so I can't rely on a rrule-Object).

If you have any questions, feel free to reopen the ticket.