The Tiny draft was not cleared after closing the modal.
Steps to replicate:
Create a new event with the following:

1. Title: Event 1
2. Description: This is draft 1
3. Edit the event. Change the description to "This is draft 1 (edited)"
4. Wait until the console.log said "tiny_autosave/id_description: Saving draft"
5. Close the popup. Do not Save
6. Click the New Event button
7. Click Show more
8. Verify the TinyMCE's content

Expected: The content is empty
Actual: TinyMCE still loads the previous content: This is draft 1 (edited)

It can also be reproduced in other cases, like creating a glossary, adding an entry without saving it and then, in a new tab, creating another glossary entry.