The UIDs file sets gitlab-runner's home directory to "/var/tmp/minio". This seems to be a copy/paste error from the line above. According to the docs at https://docs.gitlab.com/runner/install/freebsd.html , gitlab-runner does require a home directory.
A commit references this bug: Author: swills Date: Wed Jul 19 16:58:14 UTC 2017 New revision: 446208 URL: https://svnweb.freebsd.org/changeset/ports/446208 Log: Fix copy and paste error in gitlab-runner home dir PR: 219345 Reported by: asomers Changes: head/UIDs
Fix committed, thanks for reporting.