Drafts do not save when adding or editing a page unless you close the tab or window and click "Leave this Page"

Symptoms

When editing a page, the drafts do not actually save unless you close the tab or window gracefully, and click "Leave this Page" on the confirmation.

When adding a new page, even when you close the window, it does not prompt if you want to leave the page, and still does not save any draft.

Steps to Reproduce

Adding

1. Create a page but don't save it
2. Leave it for longer than the time a draft should be saved
3. In another tab/window, open the drafts page under the user menu and see the draft does not show up
4. Exit the window/tab by any means
5. Observe there is still no draft

Editing

1. Create a page
2. Save it
3. Edit the page
4. Add some changes
5. Wait for the time until a draft should save (30 seconds by default)
6. In another tab/window, open the drafts page under the user menu and see the draft does not show up
7. To reproduce the draft never being saved, kill the browser forcefully (for example "kill -9" in Linux/Mac)
8. To reproduce the draft being saved at window close or tab close, close either the window or tab and click "Leave this Page"