Thanks.
Please note that this is not supported (it will not find the correct PR to decorate), and this field only accept numeric values.
Those 2 properties :
sonar.pullrequest.key=PR-(System.PullRequest.PullRequestId)
sonar.pullrequest.branch=(Build.SourceBranchName)
Are automatically filled for you, you don’t have to worry about them, so you can safely remove those from extraProperties.