I noticed that calendar events which were created by activities appear both in the Timeline and the Upcoming Events block. However, both blocks also display information that's missing from the other one. If you want all the information on your dashboard you have to add both blocks but then you might have some duplicate entries.
Could the timeline block maybe be extended to show all info that the Upcoming events blocks is showing at the moment, i.e. all upcoming calendar events, not only those created by activities? Then we could deactivate the Upcoming events block in our Moodle installation.