This can happen when the appropriate SCM plugin could not be detected. There should be more details about this in the scanner logs.
The other issue, with “Unexpected exception while clearing reviews”, we already know about, you can track it on SONAR-12243. The ticket includes the workaround to make PR decoration work:
Two additional permissions are currently required on the GitHub App in order to decorate pull requests on private repositories:
- Pull Request - Read Only
- Commit Status - Read Only