SonarScanner blame falling back to GIT_NATIVE_BLAME - how to debug?

So is it GIT_FILES_BLAME or GIT_NATIVE_BLAME as suggested here?

Also, I’m trying to keep a lean Docker image on which SonarScanner is running. Is there a way to pin the blame algorithm to use JGit in a similar manner? I can’t find any documentation on the sonar.scm.use.blame.algorithm at all (not even on the Analysis parameters page which has some of the sonar.scm.* parameters documented) so I don’t know what the allowed values are.