After upgrading the Bitbucket Server Integration plugin to 3.0.0 our Mutlibranch Pipeline jobs failed to work. It was like someone disabled all jobs manually, but the "Disable Multibranch Pipeline" button didn't do anything. If we went into the configuration and saved it without any changes, the jobs were active again. After some successful scan/run there were in "disabled" state again. We tried to downgrade our Jenkins engine first from 2.303.1 to 2.289.3 but the problem was still there. After we downgraded the Bitbucket Server Integration plugin from 3.0.0 to 2.1.3 everything was perfect again.

Here are the relevant event logs when this happened:

Multibranch Pipeline Events
[Wed Sep 29 22:00:38 CEST 2021] Received com.atlassian.bitbucket.jenkins.internal.trigger.BitbucketWebhookConsumer$BitbucketSCMHeadEvent UPDATED event from our_repository with timestamp Wed Sep 29 22:00:38 CEST 2021
[Wed Sep 29 22:00:38 CEST 2021] com.atlassian.bitbucket.jenkins.internal.trigger.BitbucketWebhookConsumer$BitbucketSCMHeadEvent UPDATED event from m_sw_main with timestamp Wed Sep 29 22:00:38 CEST 2021 processed in 44 ms

And then:

Started on Sep 29, 2021, 10:14:00 PM
Build disabled
Done. Took 0 ms
No changes

Replication instructions

• Create a new Multibranch pipeline project pointing to a remote repository. Ensure that no triggers have been enabled
• Create a second Multibranch pipeline project pointing to the same repository. Enable the push trigger for this project
• Push a change to a branch on the repository that both projects have successfully scanned.

Expected behaviour
The second job builds as normal, and no behaviour is observed on the first

Actual behaviour
The branch the change was made to is disabled on the first project

Workaround
There is no workaround for this issue