Pipelines for forks of www are failing

I've recently noticed that the pipelines are failing without any apparent reasons for www forks. Why is that happening? 🤔

Examples:

• !8152 (merged) (failed) - merged into a new feature branch I created myself => !9053 (merged) (passing)
• !8747 (merged) (failed) - merged into a new feature branch that I created myself => !9041 (merged) (passing)

Slack thread: https://gitlab.slack.com/archives/C413US389/p1513605891000653

cc/ @axil @rspeicher any ideas?