Cold-War intelligence doctrine and 2025 retrieval research independently converged on the same two-axis source model — reliability apart from credibility — and on the same failure mode

Two fields separated by eighty years and every institutional boundary encode the same abstract source-evaluation model and then run into the same failure:

• Intelligence tradecraft. The Admiralty Code (NATO STANAG 2511 / AJP-2.1) grades each report on two axes meant to be independent — source reliability (A–F) and information credibility (1–6). Yet evaluators cannot hold the axes apart: they avoid inconsistent pairings and over-weight the source's track record.
• Machine retrieval. Reliability-aware RAG re-derives the split — estimating source reliability separately from document relevance — and AuthorityBench finds the same bleed: feeding a model the document's own text degrades its authority judgment, because content contaminates the reliability signal.

The shared shape is precise: trust in the source is a distinct quantity from the merit of the specific message, and both human and machine evaluators struggle to keep the two apart, with reliability judgments contaminated by content. Each field arrives at the two-axis design because the problem structure demands it, and each discovers that the axes leak.

What kind of recurrence this is. Unlike the watermark case (an explicit metaphorical borrowing of an old term) and unlike the append-only-log case (diffusion of a named, two-decade-old software pattern), the RAG literature shows no visible common ancestor with NATO doctrine — RA-RAG and AuthorityBench do not appear to cite the Admiralty Code. On the evidence in hand this reads closer to genuine convergent evolution than to loanword or diffusion. That is a claim about absence of citation, though, not proof of independence; the common-ancestor check that resolved the append-only case has not been run here, so "independent" is held provisionally. It also indicts the vault's own single source-tier field, which fuses the two axes into one number.