When you create an event service time, you have the option to include or exclude the entered data from the dashboard and regular reports via the Include in regular reports option. See Event Option - Include in Regular Reports.
If that option is turned on after saving records, then the saved records won't show up on the dashboard.
This is because when you save entries on the input screen, it copies the option Include in regular reports to the records. Changing the service definition after the fact, doesn't update the records.
Fortunately, the solution is easy:
Make sure the Include in regular reports option is on (or off) as desired for the event service time.
On the Input screen, find the event entry.
Change all the saved numbers - e.g. add "999" in front. Save. Change them back and save again.