SYMPTOM:
When users execute a report containing a running metric, such as RunningSum(Contribution), and a filter (metric qualification) on the metric, such as RunningSum(Contribution) > 0.5, only 50% of the data is returned by the running metric:

CAUSE:
This issue occurs because the calculation of the metric 'RunningSum(Contribution)' is made at execution time. After filtering, a new calculation is performed and new values are displayed with the original attribute.
The application is working as designed. Note the results in the following screen shot obtained by removing the filter RunningSum(Contribution) > 0.5 and re-executing the report:

Applying the filter to the report will allow only the first three records to remain since 63.22% > 0.5. The new calculation is performed and a new value will be displayed with the original attribute, i.e. RunningSum(Contribution) displaying data from 27.26% onwards.