A real-robot verdict is (policy x deployment stack) - when the stack changes materially, old verdicts expire

Symptom

walk_v5 stood condemned as "kicks wildly" and walk_v6 as "cannot walk unassisted" - but those verdicts were issued under an earlier deployment stack (--heading did not exist yet, several fixes had just landed); only v7 had ever run under the current unified stack.

Context

New sim evidence sharpened the doubt: a same-harness four-version sweep showed v6 was the HEALTHIEST archive at the real operating point (cmd 0.15: dominant frequency locked at 2.50, steps 35:35 perfectly symmetric, foot distance 203/190 mm best of four, mean tilt 4.2 deg, saturation 15%). A full re-test under the unified stack was scheduled with per-version questions and a pre-filled interpretation table ("判读表(预填假设,回来对号)"): e.g. v6 walks + frequency ~2.5 -> old verdict was the stack's fault, v6 becomes the comparison champion; v6 walks but at ~1.25 -> period-doubling on hardware = confirmed plant gap, actuator fitting promoted to mainline; v5 no longer kicks -> the kicking was an old-stack artifact.

Change

All four versions re-queued on hardware under one stack (same torque limits, slew profile, heading loop, logging), with the version-specific legacy profile pinned; verdicts held provisional until re-issued.

Outcome

The re-test design separated policy properties from stack artifacts before any policy was permanently written off - and turned each outcome into a specific conclusion via the pre-filled table.

Mechanism

A deployed behavior is produced by the policy plus everything between it and the motors (heading loop, slew limits, torque caps, clock); verdicts implicitly condition on that whole stack. Fixing the stack invalidates the conditioning, so old failures may be stack artifacts and old successes may not survive either.

Applies when

• deployment tooling (limits, filters, loops) changed since a policy was last judged
• deciding which historical policy is the rightful baseline
• a sim sweep contradicts an old hardware verdict