Dpl v1 causes "illegal option" error when passing body: value

I’m trying to deploy release notes to a GitHub release by using the deploy.body: “advanced option”. However the deploy fails with

invalid option "--release_notes=### New Features <full release notes elided> (571973e5)"

My deploy section is

  - provider: releases
    api_key: $GITHUB_TOKEN  # Set in the repo settings page as a secure variable
    file_glob: true
      - build-macos/KTX-Software-*.pkg
    body: $RELNOTES
    skip_cleanup: true
    draft: true
    prerelease: true
      tags: true
      condition: $TRAVIS_OS_NAME = osx

I get the same error if I change to body: "$RELNOTES"

RELNOTES is an environment variable containing the release notes.

It looks like dpl v1 is not quoting the value of body when passing it to the --release_notes option.

After this error appears there is no further output so the build is cancelled 10 minutes later.

This is the same issue as https://github.com/travis-ci/dpl/issues/155. There seems no solution except the release_notes and release_notes_file options in dplv2.

Why was it though a good idea to replace an issue tracker with a bulletin board system?