Unable to Reproduce
When you right-click on a source report file in Eclipse 2021 06 with TIBO JasperSoft Studio Eclipse Plugin installed and select compile it does nothing. No errors are seen but no compiled report file is created/updated. If you try the exact same with 2021 03 Eclipse it works.
MacOS 11.4 (Big Sur)
Eclipse 2021 06
I have not tested this on different OS's
If you use the standalone TIBCO JasperStudio it works.