What is the version of BI, SP, patch level?
If you see the issue across different reports, then test it in other environments like QA and if the issue is only with this environment check if there is any issue on installation configuration side.
If issue is consistent across all environments you use.Try to install server on a small scale in a test system and see if the issue persists with the version of software you are using, If so, I suggest you to raise it with SAP.
Thanks
Mallik