We have integrated Jenkins with Github to build jobs as and when PR is raised with the github pull request builder plugin.
From yesterday when the job gets triggered we are seeing this failure "java.lang.NullPointerException" even before the pipeline starts to execute and the job reports the status to github as failed. Also in the console there is a log that mentions "Resuming build after jenkins restart" but there was no restart at the time when this job was triggered

But in a little while the job starts executing and then passed the build again in jenkins?

This happens often if we retrigger the job but not always!!!

Any idea on why this is happening

Jenkins Console:
Resuming build at Thu May 09 16:30:11 UTC 2019 after Jenkins restart [Pipeline] End of Pipeline Setting status of b9d1bd39cfae59d607b1a8060f2a8ae2fc180a1e to FAILURE with url https://JENKINS_URL/job/JOB_NAME/103/ and message: 'Build finished. ' java.lang.NullPointerException Finished: FAILURE