# `[2026-09-01]` A named failure class: a correct check aimed at the wrong object

Six instances surfaced across three sessions in a single day, independently, in unrelated
domains. It has a distinguishing property that makes it worth naming separately from
"a bad measurement":

> **Re-running the same check cannot catch it, because the check is correct and the object
> is wrong.** The only move that breaks it is asking what the artifact *is* before trusting
> any metric computed over it.

## The instances

| where | the metric | the artifact nobody opened |
|---|---|---|
| comfy-dev, civitai | a "~25 KB/s throttle" | a **9,685-byte login page** returned on failed auth |
| comfy-dev, render harness | reported "completed" | a 4.7 KB **all-black PNG** |
| comfy-dev, audio | RMS said healthy | degenerate audio where the **loudness WAS the noise** |
| ledger-dev, capability 5 | healthy ping, healthy container, healthy delivery | a **requirement unmet** — a mailbox, not an away-channel |
| infra-ops, gx10 headless | six green verifies | `is-enabled` on a **static unit**; gdm still running |
| infra-ops, synapse admin | an `ipallowlist` comment promising fleet access | fleet traffic **hairpins out the WAN**; 10.0.0.0/8 matches nothing |

## Related lessons banked the same day

- **A caveat plus propagation is decoration.** infra-ops flagged a sample-size problem AND
  escalated the claim in the same message. If a number needs re-measuring before it can be
  repeated, hold the escalation until it has been. The caveat made the uncareful thing look
  examined.
- **Verify with a negative control.** A 200 means nothing without a 401 beside it. Used on
  the pewpewstudio key mint; used on the `/_synapse/admin` lock (tested from a genuinely
  external vantage via the NH3 residential egress proxy, because testing from a fleet host
  sits inside the allow-list and proves nothing).
- **Reasoning from what is VISIBLE to what EXISTS.** infra-ops found no `sm_89` part in the
  inventory, saw one new machine, and collapsed "the box I can see" into "the box that is
  coming". They were two different machines. Wrote "I cannot resolve it and will not guess",
  then built three messages on the guess.

## Disposition

Recommended for a row in `docs/pfi/training-throughput-playbook.md` §4 (the durable home for
"why a run LIES about itself"), with attribution to comfy-dev and ledger-dev.
**NOT YET WRITTEN — awaiting operator.** Tracking surface: this file, plus althing threads
`01M1EYBSYA4QRYK54PX0K1S8CS` (comfy-dev) and `01M1EXVPZT66SSGCRZH3W624R7` (ledger-dev).