This article provides steps to take if running into caching issues, in a local / client machine, including deleting temp files.
If it is noticed that only a small set of users, or only specific individuals are complaining of slowness in Advanced Reporting, this can be attempted, since the cause could be in the desktop / personal computer, that they are using.
This is unlikely to help where slowness is experienced by the entire user base.
If having caching issues in the Advanced Reporting UI:
Note: These instructions are for a client machine, running a Windows OS. This is not about the Jaspersoft server itself.