Graphs collect item data based on criteria what you mention in graph attributes. Beware of Start Date and End Date attributes. This date is not your release or sprint start date.
Start Date is the starting point to look for item creation date. An item created one day before graph start date, will not be counted in the graph.
To see all board items in your graph:
- Check the oldest item creation date on board
- Set this date as your graph Start Date
- Set End Date by which you want to know item latest progress