Hi James,
This issue was already reported to SAP. It looks like to me that your temp file is not deleted, only when you uses the Export button of the CrystalReportViewer. Correct me if I am wrong.
What happens if you directly exporting the report using code? Does you see the same behaviour when you are exporting the reports through web-application code?
Can you please mention the version of CR4E you are currently using?
Have you checked the behaviour on latest version of CR4E i.e. 12.2.218?
Can you please be more specific, that at which exporting format you are observing this behaviour?
Thanks,
Shailendra