After the mobx / karaoke PR, lint errors would no longer cause the build in dashboard to fail:
https://github.com/jenkinsci/blueocean-plugin/commit/e8c0f65d888a03385ea9f4d62c166f016755b512

The prior commit in master behaves correctly, where lint errors in dashboard will fail the build:
https://github.com/jenkinsci/blueocean-plugin/commit/7adb6826eaeb903fcd2c47e7317c38d1e25bd885

michaelneale is able to reproduce this in his local environment as well. See PR for additional details:
https://github.com/jenkinsci/blueocean-plugin/pull/1059

This could be a timing issue, as quite a lot of extra code and files were added in the karaoke PR.