File C:\ProgramData\Parallels\RASLogs\RAS Reporting\reporting.log on the server with RAS Reporting installed is not archived automatically.
Parallels Engineering team is aware of the issue and is working on the resolution.
If you are using RAS Reporting 17.1.2 or older, please update to the most recent version from here.
The fix for RAS Reporting 18.0 is not available for download yet.
Note: Please take into account that RAS Reporting must be of the same major version as the RAS farm. Please do not use RAS Reporting 17.1.3 with RAS 18.0.