Changes (new items) are not displayed in Content Scheduler when navigating the timeline.

Steps to reproduce:
1. Login as admin
2. Go to Page
3. Create new Landing Page
4. Add Content Scheduler block
5. Open block settings
6. Add two items: Media/

7. Confirm default date
8. Add 1 more item: Media/Multimedia
9. Set the publication date two days in the future.
10. Submit block
11. Publish Landing Page
12. Go to Edit mode of created Landing Page
13. Expand the timeline and go to the time when third item should be added.

Expected:
3 items are visible in Content Scheduler: Files, Images, Multimedia

Actual:
2 items are visible in Content Scheduler: Files, Images

Note:
Doing the same operation in View mode correctly displays 3 Content Items.