The probe that asked the operating system never errored: it just said False, forever, while her model sat resident. A dead sensor doesn't fail loudly; it reports a plausible value until you ask the source itself.
Two ways existed to answer 'is her model on the GPU right now'. Asking the operating system looked reasonable, but masked process names and unavailable per-process memory made it answer False permanently, and two features downstream simply never ran. The fix was asking the model server itself, the one component that always knows what it has loaded.