We are seeing duplicate builds triggered on Jenkins multibranch pipeline projects. Builds are normally triggered using push notifications from Bitbucket using this plugin: http
I'm using a multi-branch pipeline too and I may have some information for you.
When you create a "GitHub organization" job in Jenkins and add the relevant Git information, you are also required to select how Jenkins builds are triggered and how often:
Jenkins will scan the repositories under your configured GitHub organization as often as you set it.
Then, Jenkins will automatically trigger a build as soon as it finds that a new commit has been committed (as long as the Jenkins-Git webhook is configured).
When branch indexing takes place, it also triggers a build.
In other Jenkins job styles you are able to configure "Do not allow concurrent builds" but I couldn't find this setting for a multi-branch job style.
I hope this sheds some light on the matter.