iCalendar sync issue: Unable to remove declined event from synced account

Device: MacBook Pro M1 Pro

MacOS: Sequoia 15.3.1

But the issue has been observed for at least the last four months, but before then the specific condition wasn't met, so it could have been there since forever.

Application: iCalendar

Detailed Description:

I set up a few email accounts (Outlook & gmails) to sync with my iCalendar on my Mac. It has worked really well -- nearly perfectly! Whenever I get invites to events from a synced account -- outlook or gmail -- I get the notification quite promptly on iCalendar and am able to accept or decline as needed.

The only situation in which it doesn't work is when I get this blast invite to a seminar that a professor regularly sends to an email listserv of ALL STUDENTS. It came through my outlook account.

It's a little annoying; however, a simple decline to each invitation should suffice, right? The issue is that the event would get created on my iCalendar regardless of my response. I can decline on my Outlook account, and the event would be removed from my Outlook calendar, but it would be stuck on my iCalendar. I can't delete it manually, seemingly because it is an event synced from a different account. In the below screenshot, I `right clicked` on the event to delete on iCalendar, then click `continue`, but nothing happens.

The only way to remove this issue is to `disable` my Outlook account from iCalendar app, wait a few minutes for the events to be removed, restart the app, and re-enable the account for the events to be repopulated. Only then, the declined invite would not be added.

This behavior is not seen anywhere else in other invites from the same Outlook nor other gmail accounts. My suspicion is that, it is because the invitation was sent via a listserv, so my email wasn't technically on the invite list, at least not on iCalendar. If I click `get info` on that event, generally it would show a list of invitees and their responses. My name is not on the list, so iCalendar doesn't check for it???

Curiously, this issue doesn't seem to affect my iPhone.

It's not the end of the world, but it happens frequently enough and the solution takes enough effort to annoy me very much. This could potentially be an Outlook issue, but I would really really appreciate someone here taking a look into it.

Thank you so so much.