Occasionally, a push to a branch triggers two builds on the corresponding branch in a multibranch pipeline. We are using the GitHub as branch source, and have added a organization wide GitHub webhook on push only. I am not sure about the relationship between the GitHub plugin and the GitHub branch source plugin.

On normal builds we see the following two lines:

Started by GitHub push by (author)
Push event to branch master at 9:31:27 AM on May 2, 2019

Each of the builds that are triggered twice has just one of the above lines, i.e.

Started by GitHub push by (author)

and

 Push event to branch master at 9:31:27 AM on May 2, 2019

respectively.

Can anyone shed light on what these two lines mean?

The Jenkinsfile has this property:

properties([
  pipelineTriggers([githubPush()]),
])

Removing it does not seem to have any noticable effect though.