Runner issue with bitnami/kubectl:1.14

Summary

Unable to run bitnami/kubectl:1.14 image

I can run the above image locally as docker run bitnami/kubectl:1.14 --help

On gitlab it seems the image runner attempts to change docker entrypoint and prepends sh before content of script

Job error:

Error: unknown command "sh" for "kubectl"

Did you mean this?
	set
	cp

Run 'kubectl --help' for usage.
unknown command "sh" for "kubectl"

.gitlab-ci.yml

...
deploy to staging:
  stage: stage
  image: bitnami/kubectl:1.14
  script:
  - config set-context --current --namespace=foo
  - rollout restart deployment/frontend
  environment:
    name: prod
    url: <removed>

Steps to reproduce

What is the current bug behavior?

image runner fails with bitnami/kubectl:1.14

What is the expected correct behavior?

image runner should work with bitnami/kubectl:1.14 (I need kubectl 1.14)

Output of checks

This bug happens on GitLab.com