Just a note to other new GitLab pages users who might end up here through a search - it’s kind of a flaky service.
That’s a bit harsh on it because that’s judging it by some pretty high standards but there are frequent delays with the builds/runners and sporadic downtime occurs somewhat frequently (at least for my tastes).
But, it is free and that’s great, just be aware that builds can sometimes take over an hour to execute and there might be other bumps in the road.
So the original issue here in this thread is common and isn’t indicative of a problem with Hugo, it’s a GitLab thing.