New Duplicate calendar events on users calendar when added to Attendee list; is that normal?

I’m not sure if this behavior is intended/normal, or if I should look into a bug issue on Github.

Today, as the Admin, I made an entry on my cloud calendar, which is a shared calendar but only shared with my normal user account. While initially authoring that entry I added my normal user account to the “Attendees” list.

Switching over to my normal user account I was surprised to see two calendar entries showing. One was via the shared calendar and that I expected. The other was a duplicate entry added to the named calendar at the top of my calendars in the left side panel. This was not expected at all.

Then to see what would happen, I switched back to the admin and deleted the “Attendee” list and saved the event. Going back over to my normal user account I still see two calendar events, but the one that was added to my first named calendar now appeared in strikethrough font denoting a canceled event, but the shared calendar entry looks fine still.

Somehow in my mind, I assumed Inviting Users/Adding Attendees would merely show the event on the attendee’s calendar and not create a new object in their first listed calendar.