TFS Burndown chart doesn't appear to be correct - potential bug

Question

PLEASE SEE THE EDIT BELOW, THE REPORT SEEMS TO USE CACHED DATA?

I cant figure out why there are 89 hours of work remaining, when I have 3 Active Work Items totaling 44 hours:

My Burndown Chart:

Remaining hours on 3 blocked tasks equals 44 hours:

I do set the completed hours when I close my tasks:

What am I doing wrong with the remaining vs completed hours? is this a bug in TFS?

This seems to be different to previous experiences, I've just started a new job.

EDIT:

Today the report is correct, how do I stop the caching happening?

Answer 1

This burndown report reads from the cube and not from the operational datastore. The cube is processed every 2 hours.