The workflow sidebar shows many instances of the "Label This Build" link, when a finished Pipeline build which uses the P4 plugin is selected. I attached part of a screenshot, which shows some of the links.
This is very similar to https://issues.jenkins-ci.org/browse/JENKINS-35176 , https://issues.jenkins-ci.org/browse/JENKINS-39233 and maybe https://issues.jenkins-ci.org/browse/JENKINS-38204 .
- is related to
JENKINS-29326 Workflow sidebar has duplicated Git Build Data links