The Bitbucket APIs were recently changed for GDPR reasons, replacing usernames with UUIDs in many places. There was work to accommodate this change in JENKINS-57209.

However, since these changes, pushes to Bitbucket are failing to trigger Blue-Ocean-created builds in Jenkins.

The root cause seems to be that Blue Ocean populates the build owner with a UUID value in the build configuration. Manually replacing this with a Bitbucket username fixes the problem and triggering works again.

See the attached screenshot of an example problematic configuration, containing a UUID as the owner.