Jobs for this plugin are occasionally timing out, for example: https://jenkins.ci.cloudbees.com/job/plugins/job/ghprb-plugin/867/
Since it's already running at 30 minutes, I'm wondering if there are improvements that could be made to the underlying infrastructure. If that's too hard/timeconsuming/etc, perhaps you could add the timestamper and extend the timeout? Then I could do a bit more troubleshooting on subsequent builds.
Worth noting, it was still downloading the maven requirements when it aborted in the above example.
Happy to provide more info if you need it. Cheers.