How to stop iOS/Siri from assessing Outlook Spam Email Folder and adding them as calendar invites in iOS calendar

I've seen this same question asked in a number of places and all threads locked as unresolved. Let's try again since I've found no solutions short of deleting the calendar (essentially nuclear option against Outlook)

I have an Outlook/Exchange calendar on my iPhone iOS26.1 and since installing this OS I have been plagued with the regular flow of email within Outlook Spam folder NOW being picked up by IOS and added as repeating calendar entries. Why iOS/Siri is looking to a spam folder is anyone's guess. I've also checked that there's no unexpected calendar subscriptions and everything seems normal. I've even go so far as completing disabling all Siri functions and they're still there following hardware reboot.

I physically checked the Outlook calendar (via OWA) and there's no spam entries in the calendar. So this is something that IOS is doing to "merge" real calendar entries with stuff it found in emails.

How do we stop this? These entries cannot be removed and frankly should never have been added (massive security issue).