If any value needs to be displayed in Artist app then that value needs to be added in Local details.
-Because Value of local details is public and can be shared with artist.
-But value of event details is private so it can not shared with artist and so the value will not display artist app
So how a value added in local details and how it will show in Artist app and itinerary is described here:
At first, For example, need to be created "Get In" field and active "Start-Time" checkbox in Local Details by SETTINGS/BOOKING/Local Details Settings.
So, This get in Start Time value will show in itinerary and Artist app also.
You have to add "Get In" in event date local details and add the "Start-Time" value as get in value.