Skipping cache extraction due to inability to make the cache file path relative to the build directory (is the build directory absolute?)

I’m getting the error Skipping cache extraction due to inability to make the cache file path relative to the build directory (is the build directory absolute?) when trying to restore cache on a GitLab SaaS runner.

What could be the cause of this error? Since it is a SaaS runner, I didn’t configure the runner myself.