Close a question with an audit, then freeze the wording - later symptoms may not reopen it without new hard evidence
frozen-verdicts-semantic-boundaries.When an audit closes a hardware-vs-policy question, record the closing evidence, freeze a citable wording for future recurrences, and set the reopening bar explicitly; separate robustness perturbations from plant-truth questions so a DR rung's failure can never silently reopen a closed measurement.
Symptom
Recurring directional bias on the robot kept re-suggesting "maybe the hardware/COM/mechanics are asymmetric", threatening to re-litigate questions that audits had already closed - burning attention each time a descendant policy leaned or drifted.
Context
Two boundary decisions were written as permanent: (1) semantic separation - "S2④ COM ±20mm = 纯鲁棒性扰动,不再承担「解释真机后仰」任务" - if the COM-DR rung degrades, the ONLY allowed conclusion is "policy insufficiently robust to COM uncertainty"; reopening "is the CAD COM wrong" is forbidden because the mass audit was completed and closed (@63f9212). (2) a frozen wording for chirality, to be quoted verbatim whenever left/right bias appears in later rungs: observed directional bias = policy-level spontaneous symmetry breaking; plant asymmetry = no supporting evidence after the mass + model symmetry audit; mitigation candidate pi_sym queued, not blocking. The evidential basis was quantitative: the root policy was perfectly symmetric under +/-6 N*s pushes (40/40) while descendants broke (17/40, 13/40) - "手性是 S2 训练中获得的, 根没有; 机械侧已双 PASS 关案, 不重开".
Change
Closed questions carry (a) the audit commit that closed them, (b) a frozen citable wording for recurrences, and (c) an explicit evidence bar for reopening ("无新硬证据不得重开").
Outcome
Later chirality observations (C2's 15 pp turn gap, hip_roll drift bias) were handled as policy-lineage properties with policy-side mitigations, without a single hardware re-audit cycle.
Mechanism
Symptom classes recur under different guises; without a frozen verdict each recurrence re-runs the same expensive investigation and risks a different (worse-informed) conclusion. Freezing verdict plus wording converts recurring symptoms into citations, while the evidence bar keeps the closure honest rather than dogmatic - the root/descendant symmetry comparison is what makes "it's the training, not the machine" checkable at any time.
Applies when
- a recurring symptom keeps suggesting an already-audited hardware cause
- writing conclusions for a completed calibration/audit
- a DR rung's degradation invites re-measuring the plant
“若 S2④ 退化,结论只能是「当前 policy 对 COM 不确定性不够鲁棒」,不得重开「CAD COM 是不是错了」… 手性冻结表述 … Plant asymmetry: no supporting evidence after mass + model symmetry audit … 无新硬证据不得重开机械不对称”