Gitlab-runner in parent project context non-functional

Hi,
I tried to follow Pipelines for merge requests | GitLab to manually run a CI job in a runner in the parent project context. Yes, the project is using a premium service on gitlab.com. Still, this didn’t work, all I got was an error message “An error occurred while trying to run a new pipeline for this merge request.” Does anyone have experience running such CI jobs? I’ve opened an issue for GitLab gitlab-runner: "An error occurred while trying to run a new pipeline for this merge request" (#348989) · Issues · GitLab.org / GitLab · GitLab

Problem solved: had to add

include:
  - template: 'Workflows/MergeRequest-Pipelines.gitlab-ci.yml'

to .gitlab-ci.yml