Emails defined in CC aren't encoded when sent to the server. It means that characters like + for aliases are wrongly interpreted as space

The url is built here : https://github.com/jenkinsci/cloudbees-jenkins-advisor-plugin/blob/master/src/main/java/com/cloudbees/jenkins/plugins/advisor/client/AdvisorClient.java#L75-L78

It’s using: https://github.com/jenkinsci/cloudbees-jenkins-advisor-plugin/blob/master/src/main/java/com/cloudbees/jenkins/plugins/advisor/client/AdvisorClientConfig.java#L50-L60

And it’s manually handling the encoding here: https://github.com/jenkinsci/cloudbees-jenkins-advisor-plugin/blob/30d1df36b4f9de4ef6308b6873a6d0eaa1aa97ad/src/main/java/com/cloudbees/jenkins/plugins/advisor/utils/EmailUtil.java#L19-L24

only the CC parameter is “encoded” and this encoding function is just taking care to replace comas to separate emails