According to this post burndown/burnup get one live ( read: not from warehouse ) data point.  In the readme for 6.0.2 ifix12 package one can find:

[APAR PI77546] [Burnup/Burndown reports hide live point when category select (413304)] [https://jazz.net/jazz/resource/itemName/com.ibm.team.workitem.WorkItem/414462]

Our users (or at least one ) has pointed this out to us and I thought it was because the Data Mart jobs were running at 0300.  Over the weekend I changed to 2300 ( skipping a day ), but that had no effect on the last point having 0 value ( or arcing up to infinity ).   Based on the defect above, I created a simple burndown and when category is selected, the right-most point drops to 0, with no categories, the line stops "yesterday"

ODS jobs in DCC are running each 240 minutes, so I don't understand why the last data point remains at 0.

ADDENDUM:   It appears that the live point is drawn at 0 if Category is chosen otherwise there is a non-zero value.