Jenkins CLI is not reporting a failure error code when builds fail.
This is a problem when you call one build from another in the command line. In console output you see
Stuff happens...
C:\JenkinsNew\jobs\project1\workspace>java -jar "C:\JenkinsNew\jenkins-cli.jar" -s "http://jenkins:80" build "project2" -s
Completed project2 #27 : FAILURE
Stuff happens...
Then the build is passed, and erroneous emails are sent.