How do I stop my calendar from adding calendar invitees?

It seems Apple was fantastic remembering what invitees I was using in specific Events. It started remembering them from one single Event on the iPhone!

We created a Shared Calendar to make it easier. But even after creating 18 Events, removing that invitee 18 times choosing the Shared Calendar, Apple refuses to automatically remember and not add an invitee.

Is there a way to stop Apple from adding the invitee? Adding it to the Shared Calendar is ok since it is on the same page, but remembering the invitee is a pain since it is on a different page.

[Re-Titled by Moderator]