xxx(null)@p##-caldav.icloud.com

For years now I have been unable to delete or change a repeating calendar appointments on my iPhone that were created using previous versions of iCal. The appointments seem to be ghost appointments tied to an older, somehow archived version of ical called [(null)@p##-caldav.icloud.com] that can't be accessed. I call it a ghost because I can make it dissapear off a calendar only to have it come back with an operating system update. Hence my writing of this today with the latest Monterey update across all devices. How can I get rid of this "ghost" without getting rid of the history of those appointments that I need to keep a record of?

example calendar:

on iCloud: Home (syncs with everything)

on iPhone same (duplicate?) calendar now possibly archived: Home[(null)@p##-caldav.icloud.com]

appointment was made using the Home calendar and then was assigned to the "null" calendar

• I can delete or change these appointments on my Mac but it doesn't change it on my phone.
• I can go in on the iPhone and turn off the caldav.icloud calendars but this doesn't make the problem go away, I just don't see it everyday. Additionally when there is an operating system update the ghost appointments show back up, I assume because the update authorizes all calendars...

I know I can delete the calendar from my phone - I am then told it will delete everything associated with that calendar. My question is if I delete the caldav.icloud calendar will it delete old appointments that I need to keep record of or will those appointments still show up in the apparently parallel calendar on iCloud? i.e. have those old appointments been tied to the caldav.icloud.com calendar or to the original calendar set up on iCal application?