Steps to reproduce:
1. Enable asset upload options via etc/listproviders/event.upload.asset.options.properties
2. In Admin-UI, Click "New Event", upload media, upload an asset, submit
3. Click "New Event", upload media, do not upload an asset, click through to summary page.
Actual Results: The previous upload asset shows on the summary page and is added to the second New Event upon submit.
Expected Results: No uploaded asset shows on summary page or is added to new event, unless one was deliberately chosen.
Workaround (if any): Reload the admin-ui page between new media uploads.