With a recent upgrade of plugins I can no longer abort Pipelines waiting on an input step.

See the attached screenshot, but basically hitting the Abort link hits a 404 endpoint.

The screenshot was after a resumed Pipeline, but I can also reproduce this with a simple input step, e.g.:

node {
  stage('Build') { sh 'echo "Hi"' }
  stage('Deploy') {
    input message: 'Deploy?', ok: 'Ship It!'
  }
}