Unable to publish HTML report from local Jenkins

Sitespeed.io dockerized: 9.8.1

I know this question has been asked several times, but I have yet to see a documented resolution in the issue notes. So here goes:

I am using the jenkins/blueocean docker container locally as documented at https://jenkins.io/doc/book/installing:

docker run \
  -u root \
  --rm \
  -d \
  -p 8080:8080 \
  -p 50000:50000 \
  -v jenkins-data:/var/jenkins_home \
  -v /var/run/docker.sock:/var/run/docker.sock \
  jenkinsci/blueocean

I followed the instructions at https://www.sitespeed.io/documentation/sitespeed.io/continuous-integration/#jenkins, but the resulting error is as follows:

Started by user admin
Running as SYSTEM
Building in workspace /var/jenkins_home/workspace/sitespeed
[sitespeed] $ /bin/sh -xe /tmp/jenkins338716514023622966.sh
+ docker run -v /var/jenkins_home/workspace/sitespeed:/sitespeed.io sitespeedio/sitespeed.io --outputFolder output https://www.sitespeed.io/ -n 1
Google Chrome 76.0.3809.87 
Mozilla Firefox 68.0
[2019-08-27 18:29:30] INFO: Versions OS: linux 4.9.184-linuxkit nodejs: v10.13.0 sitespeed.io: 9.8.1 browsertime: 5.7.3 coach: 3.6.0
[2019-08-27 18:29:31] INFO: Running tests using Chrome - 1 iteration(s)
[2019-08-27 18:29:32] INFO: Testing url https://www.sitespeed.io/ iteration 1
[2019-08-27 18:30:10] INFO: https://www.sitespeed.io/ 13 requests, 168.25 kb, backEndTime: 230ms, firstPaint: 467ms, firstVisualChange: 0ms, DOMContentLoaded: 413ms, Load: 457ms, speedIndex: 0, visualComplete85: 0ms, lastVisualChange: 0ms, rumSpeedIndex: 467
[2019-08-27 18:30:12] INFO: HTML stored in /sitespeed.io/output
[htmlpublisher] Archiving HTML reports...
[htmlpublisher] Archiving at BUILD level /var/jenkins_home/workspace/sitespeed/output to /var/jenkins_home/jobs/sitespeed/builds/19/htmlreports/HTML_20Report
ERROR: Directory '/var/jenkins_home/workspace/sitespeed/output' exists but failed copying to '/var/jenkins_home/jobs/sitespeed/builds/19/htmlreports/HTML_20Report'.
ERROR: This is especially strange since your build otherwise succeeded.
Build step 'Publish HTML reports' changed build result to FAILURE
Finished: FAILURE