Based on the current checks, the GPU is not started. That's a first good point. Now, let see if it succeeds.

To avoid the Windows and macOS emulation mode, the GPU CI build needs a physical machine adding some costs. So, the original intent was to only run the GPU CI build on the repo itself (i.e. not running on forks) to limit fees. The ASWF offers the GPU build capability but OpenColorIO should then try to wisely use it. Starting few weeks ago, the GPU CI build was also executed on forks!

Thanks to @Simran-B, we finally discover that the execution condition was, in fact, wrong.

As github.repository is the repo the workflow is running in, this will always be true for the official repo. Usually one would use github.event.pull_request.head.repo.full_name != github.repository as condition to prevent jobs from running if they originate from a fork, [...]