An advisor to a South African financial institution needs to know which central banks are actively involved in piloting or implementing specific API harmonisation recommendations, and whether any central bank is specifically named as partnering with CPMI on the payment pre-validation API recommendation.
The model hedged toward the correct institution but could not confirm the explicit CPMI-SARB named partnership — a partnership announced in a November 2025 brief that appears to fall outside the retrieval pipeline's effective indexing. To fill the gap, the model cited a fabricated Bank of England URL as supporting evidence, producing a hallucinated citation in place of the accessible regulator record.
The fabricated Bank of England URL generated to fill the citation gap is the key signal: the model's citation-generation subsystem produced a plausible-looking but non-existent URL rather than returning 'no source found.' This points to a citation-generation pipeline that is not gated on verified retrieval — it will produce a URL-shaped output regardless of whether a real URL was retrieved.
An advisor was asked which central bank CPMI had specifically named as its partner for advancing the payment pre-validation API recommendation under d224. The AI responded that no central bank had been publicly identified in this role and proposed the Bank of England as the closest named involvement — when CPMI Brief No. 9 explicitly names the South African Reserve Bank (SARB) as CPMI's named collaboration partner conducting joint stakeholder interviews on the pre-validation API recommendation.
The model's retrieval pipeline did not surface CPMI Brief No. 9, which names SARB explicitly. Rather than returning a clean "not found," the model substituted the Bank of England — a higher-frequency institution in CPMI-adjacent content — as the most plausible named partner. The substitution follows a retrieval-ranking pattern where the model fills a retrieval gap with the highest-prior institution, displacing the correct lower-frequency answer.
The Bank of England substitution for SARB is a high-prior-institution fill pattern: the retrieval pipeline did not surface CPMI Brief No. 9, so the model substituted the most contextually plausible high-frequency institution. This failure mode will recur whenever the correct answer is a lower-frequency named institution in a recent sub-document that the retrieval index has not fully covered — a structural property of how institutional attribution fails under sparse indexing.
AI tools we tested denied that any central bank is publicly named as CPMI's partner on the payment pre-validation API recommendation — one tool specifically proposed the Bank of England as the closest analogue — when CPMI Brief No. 9 (November 2025) explicitly names the South African Reserve Bank (SARB) in that role. For a Legal team advising a Retail Banking firm with South African correspondent relationships or cross-border payment exposure to that jurisdiction, this error inverts the relevant institutional relationship.
A briefing note, regulatory mapping document, or internal legal opinion that relies on the AI's output misidentifies which central bank is actively shaping the pre-validation standard, with direct implications for how the firm scopes its engagement obligations and product-compliance posture in that corridor.
Each finding has a stable Citation ID (RLB-F-… for aggregated case-study findings, RLB-H-… for raw per-model hallucinations) — like a DOI, the ID always resolves to the canonical finding even if URLs change.
RegLeg Specialist Panel (2026). "Finding#1 — SARB named-partner denial and Bank of England substitution — Retail Banking × Legal — International / Multilateral." Citation ID: RLB-F-INT-BIS-CPMI-API-HARMONISATION-CROSS-BORDER-2024-Q007. RegLegBrief AI Hallucination Research, published 2026-06-04. https://reglegbrief.com/regulators/j1/int/bis-cpmi/cpmi-api-harmonisation-cross-border-2024/sectors/retail_banking/legal/finding/INT-BIS-CPMI-INT-001-CPMI-API-HARMONISATION-CROSS-BORDER-2024-v1-007/
RegLeg Specialist Panel. (2026). Finding#1 — SARB named-partner denial and Bank of England substitution [Hallucination finding RLB-F-INT-BIS-CPMI-API-HARMONISATION-CROSS-BORDER-2024-Q007]. RegLegBrief AI Hallucination Research. https://reglegbrief.com/regulators/j1/int/bis-cpmi/cpmi-api-harmonisation-cross-border-2024/sectors/retail_banking/legal/finding/INT-BIS-CPMI-INT-001-CPMI-API-HARMONISATION-CROSS-BORDER-2024-v1-007/
RegLeg Specialist Panel, Finding#1 — SARB named-partner denial and Bank of England substitution [RLB-F-INT-BIS-CPMI-API-HARMONISATION-CROSS-BORDER-2024-Q007], RegLegBrief AI Hallucination Research (June 04, 2026), https://reglegbrief.com/regulators/j1/int/bis-cpmi/cpmi-api-harmonisation-cross-border-2024/sectors/retail_banking/legal/finding/INT-BIS-CPMI-INT-001-CPMI-API-HARMONISATION-CROSS-BORDER-2024-v1-007/.
@misc{reglegbrief_RLB_F_INT_BIS_CPMI_API_HARMONISATION_CROSS_BORDER_2024_Q007,
author = {RegLeg Specialist Panel},
title = {Finding#1 — SARB named-partner denial and Bank of England substitution},
year = {2026},
publisher = {RegLegBrief AI Hallucination Research},
note = {Hallucination finding Citation ID: RLB-F-INT-BIS-CPMI-API-HARMONISATION-CROSS-BORDER-2024-Q007},
url = {https://reglegbrief.com/regulators/j1/int/bis-cpmi/cpmi-api-harmonisation-cross-border-2024/sectors/retail_banking/legal/finding/INT-BIS-CPMI-INT-001-CPMI-API-HARMONISATION-CROSS-BORDER-2024-v1-007/}
}