tldr: Blue ocean should use the displayName if one is there, instead of build number (like the classic screen shot). The URIs are unchanged, just what is displayed in the column. 

------ original: ------

-JENKINS-39850- claims that currentBuild.displayName is honored in blue ocean as of now, but it is not consistent.  The following script:

node {
  stage('start') {
    currentBuild.displayName = "foo.$BUILD_NUMBER"
    currentBuild.description = "foo.$BUILD_NUMBER - desc"
    echo 'Hello World'
  }
}

Produces the attached screenshots on our system.

Expected Behavior:

The activity screen should show displayName in the RUN column.  JENKINS-39850 shows screenshots that show that to be the case.