Powershell windows runner always succeeding

It looks like this should be fixed in commit https://gitlab.com/gitlab-org/gitlab-ci-multi-runner/commit/864fdbfaaf2b93c2cd0f30205506bf264127ca3b. However, I have the following yml file which is always showing as successful. The file being imported doesn't exist and the command fails. The only way I can get an actual failure of the build is to change the command to "Exit 1".

Any suggestions on why this wouldn't generate a build failure? I'm hoping I've just missed a setting.

stages:
  - test

execute-against-sydlab:
  script:
    - $clusterCredential = Import-Clixml -Path .\tests\test-credential.xml -ErrorAction Stop
  stage: test
  only:
    - master
    - /^issue-.*$/ # Test fix branches
  tags:
    - powershell
    - windows
  allow_failure: false

My Runner config on the windows box is as follows and downloaded the runner software today.

concurrent = 1
check_interval = 0

[[runners]]
  name = "Windows CI Server"
  url = "http://git.sydlab.netapp.au/ci"
  token = "447d57e62de2f9325e30b7d8a3662b"
  executor = "shell"
  shell = "powershell"
  [runners.ssh]
  [runners.docker]
    tls_verify = false
    image = ""
    privileged = false
    disable_cache = false
  [runners.parallels]
    base_name = ""
    disable_snapshots = false
  [runners.virtualbox]
    base_name = ""
    disable_snapshots = false
  [runners.cache]
    Insecure = false