B.5.2:15.1 - Service degradation diagnosis

A service team notices recurring latency spikes during one operating window. The prompt species is AnomalyStatement: why does latency spike in the evening batch window despite unchanged nominal load?

The candidate set includes:

• queue saturation in one downstream dependency,
• a time-window interaction with backup traffic,
• and a recent mechanism regression in cache invalidation.

The backup-interaction conjecture is preferred because its timing fits the existing observations and it remains consistent with known mechanisms; the other two candidates remain live. Isolating backup traffic and comparing latency against prior windows is a possible discriminator. When that probe is obtainable and its expected contribution justifies its cost and delay, it can be selected as separate work. The conjecture itself records no observation from that unperformed probe.

Now keep the same observations and rival set but make the probe window unavailable. The qualified conjecture and its uncertainty remain; if the available comparison cannot select a winner, defer that selection. No new test, waiver or study proposal is needed just to finish the present abductive result.

In both variants, suppose an existing operational qualification independently supports a bounded diversion to a spare instance for this traffic and interval, with sufficient capacity and actual permission, across all three remaining causes. C.11 can support that service response on the available basis. Diverting traffic does not identify the cause; a causal claim about the mechanism still needs the appropriate C.28 support. If that operational basis is absent, do not infer a justified diversion from conjecture plausibility.