Why are iMovie 10.1.6 events linked?

I created two iMovie 10.1.6 events for a project. I imported media to the Project Media, which is available for all events. In the first event, I edited clips accordingly. Looks fabulous.

After I create a second event the first event material is included. I thought it would be blank since I'm creating a new event. However, when I delete a clip from event 2, it gets deleted from event 1.

What is going on? This should be ridiculously easy, simple.

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Event #1

Event 2: No media

All Events: Shows no media placed in new event yet.

Event 2: Delete first clip from event

Event 1: Clip now missing after deleting clip from Event 2

OS info