After updating from 2.0.8 this morning I discovered that none of the changes being pushed to our repos which had PR's associated with them were actually launching builds.

I did 'configure' each project post the plugin update to ensure that the config was right, but for whatever reason any PR which had changes just simply weren't launching jobs.

At this point I've been forced to roll back to 2.0.8 & after fixing the config on each project things are behaving normally again.

• Within Indexing events I can see that it's 'Scheduled build for branch: PR-136' but no build job is actually spawned
• There are 0 exceptions in the Jenkins log which give a clue as to what's going on
• From a GH point of view there are no errors associated with Webhooks
• From a Jenkins POV it is receiving the webhooks

Aug 08, 2017 2:44:25 PM org.jenkinsci.plugins.github_branch_source.PullRequestGHEventSubscriber onEvent
INFO: Received PULL_REQUEST for https://github.com/xxx/xxx from 192.30.252.34 ⇒ https://xxx/github-webhook/
Aug 08, 2017 2:44:42 PM org.jenkinsci.plugins.github.webhook.WebhookManager$1 run
INFO: GitHub webhooks activated for job xxx with [] (events: [PULL_REQUEST, PUSH])

• All PR builds in the Jenkins UI were marked as 'project disabled' - a modification to their config on disk & reloading it didn't enable the projects again
• Deleting all the PR builds on disk & then restarting Jenkins didn't appear to make any difference, it still didn't want to build them
• The branch indexing didn't say anything about skipping builds, it seems to think that they could be run

Eek?!