This site was CA PPM (SaaS).
CA Support monitored the execution plan as both the Filters and the Report ran.
Two issues were found.
CA Support identified a execution plan, which was regenerated and addressed the slow Filters issue.
Please note that a regeneration of the execution plan is an unusual event, which usually only follows a change such as a major patch. It is usually identified as occurring on a Report that has "not changed" in either design or use, but a change in the environment has occurred.
2) SQL Query
The client re-evaluated the security used in the queries of the Reports, and changed "inner-joins" to different checks.
This type of issue can occur with any poorly formed SQL query, and can be identified on-site by adding and removing conditions.
In this specific example, the reports now load Filters quickly and run in under 30 seconds.
Previously, this was taking 10 - 15 minutes.
For report design assistance, please create a "Question" at the CA PPM Communities.
For report flaws or suspected execution problems, please raise an issue with CA Support.