Using SonarQube LTS 7.9.1
SonarQube scanner for Ant 2.6.0
The page Analysis Parameters | SonarQube Docs says that sonar.working.directory points to “.sonar” directory by default and this directory gets cleaned up before each analysis.
However, it seems like the default working directory location has changed with new ant plugin version. I can see that it now points to “.scannerwork”.
The documentation should be updated.