The following steps will help you identify what is causing the Idea not to produce benefits.
Navigate to the Idea Benefits Tab and Click on Grid as per the image below:
After clicking on Grid, you will be presented with the VDT breakdown view of the produced benefits for each month as per the image below:
On the above-bolded Nodes are those that have child nodes, you can click on the arrow to see all the nodes contributing to that parent's value. The issue is always linked to nodes that do not have benefits which will be blank under that particular month. It is also important to note that any computation with a blank will result in a blank.
If there's a blank on a constant node it means that the node does not have an Actual specified, as per the image below. If it is a KPI node it means the KPI is not yet updated.
If the Targets section is empty a KPI node using variable targets might be causing the issue, see this article for more information. How to use variable baselines and targets on an Idea VDT