'This job could not start because it could not retrieve the needed artifacts' In a job with no "needs" relation or artifact dependencies

I have a 3 stage pipeline, Compile -> Testing Jobs -> Reporting

The testing jobs can take a long time, much longer than the artifact expiration, which is just long enough to allow the testing jobs to all start.

The reporting job has no "needs" block at all.

This has generally all worked fine. Now, suddenly, my reporting stage has stopped working with the message "This job could not start because it could not retrieve the needed artifacts: compile"

This makes no sense at all, the documentation doesn't apply at all, there's no explicable reason why this job should have anything at all to do with the compile job, it consumes no job artifacts of any kind.

Jobs which do no declare a need for artifacts from some earlier stage should never attempt to download artifacts from those earlier stages or fail if it cannot find them.