java -jar jenkins-cli.jar build -s currently-disabled-job throws an error:

java.lang.NullPointerException
        at hudson.cli.BuildCommand.run(BuildCommand.java:135)

The reason is that AbstractProject.scheduleBuild2 can return null, though it is not yet marked @CheckForNull.

The CLI command should instead fail with a polite message saying that a build could not be scheduled. (The project being disabled is the most likely cause, though there may be others as well.)