Let's say you have the following pipeline:

node {
   stage ("tests") {
      // do stuff
      // do more stuff
      build job: 'MyExistingFreestyleJob', wait: false
   }
}

Currently if MyExistingFreestyleJob is marked as disabled ("disable this project" is checked) the pipeline fails. This is not desired behavior, a disabled job shouldn't be scheduled for building. Instead the pipeline should skip a disabled job and let the pipeline run succeed.