docs(gemma4-charrp): RETRACT the contradiction-deficit claim — the item was ill-posed

Supersedes what commit 3446367 recorded. That message stated the A16 control
"settles a question" and quoted 12% contradiction detection against gen's 81%.
The quantization half of it stands; the deficit it was measuring does not exist.

brokkr-smithy-dev retracted the finding after the operator asked to see the
individual items. The task presented two mutually contradicting statements and
asked for "the contradicting statement" — but CONTRADICTION IS SYMMETRIC.
Neither statement was more the contradicting one, the model had no way to know
which had been inserted, and it consistently named the absolute claim: a
defensible reading that the labelling scored wrong on every single item.

The tell was there and both of us walked past it: 12% on a five-option task is
BELOW THE 20% CHANCE FLOOR. A below-chance score indicts the instrument before
it indicts the model. That should be the first reaction to a below-chance
result, not a late one, and it is now written into the README as such.

Retracted: "the model owns the contradiction deficit"; "domain tuning costs 43
points of contradiction detection" (which on a sound instrument does not shrink
but REVERSES); and every pre-fix T2 number for Gemma-4, MeroMero-v2, sec and
gen. A second defect surfaced during the fix — all generators shared one RNG, so
rewriting one task reshuffled every task after it.

What survives is real and worth separating out: the A16 control result holds.
Activation precision is close to free on this workload, every other task
identical across the W4A4 and W4A16 builds. The two staging confounds caught
before the run — the two Hub repos named NVFP4A16 that declare 4-bit
activations, and the stale chat template — were independent of the item defect
and remain load-bearing. On the corrected instrument Gemma leads the very axis
it was suspected of failing (94% against sec's 81% and gen's 50%); its actual
weak axis with thinking off is spatial composition at 69%.

Recorded as a dated superseded-claims table rather than a silent edit, per the
repo's quant-work convention, so notes elsewhere stop misleading people.

stacks/gemma4-charrp/.env.example

@@ -26,10 +26,14 @@ GEMMA4_MODEL=/tank/aimodels/gemma4-26b-a4b-it-nvfp4
 # ACTIVATION-AXIS CONTROL, for one-off benching — swap this line, recreate:
 #   GEMMA4_MODEL=/tank/aimodels/gemma4-26b-a4b-it-nvfp4a16
 # Same NVFP4 weights and the same compressed-tensors loader, but 16-bit
-# activations. brokkr-smithy-dev's 2026-08-24 battery scored 12% on
-# contradiction detection with CoT off against gen's 81%, while every other
-# task sat at 100% — the shape 4-bit input activations would produce on the
-# most reasoning-dense task, so the finding is CONFOUNDED until this is run.
+# activations.
+#
+# ⚠ THE ORIGINAL MOTIVATION FOR THIS CONTROL WAS RETRACTED — see the README's
+# "Superseded claims" section. The A16 run itself HELD and is the reason this
+# path is documented: activation precision is close to free on this battery,
+# every other task identical across builds. But the "12% contradiction
+# detection" number that prompted it was an artifact of an ill-posed benchmark
+# item, not a model property. Keep the path; do not repeat the reasoning.
 # Two minutes down each way; port and both aliases are unchanged, so no
 # consumer config moves.
 #

stacks/gemma4-charrp/README.md

@@ -42,11 +42,16 @@ control below is a swap rather than a parallel deployment.
 
 ## Running the A16 activation-axis control
 
-Why: brokkr-smithy-dev's 96-item battery scored **12% on contradiction detection
-with CoT off**, against gen's 81%, while state tracking, constraint following,
-long-context state and the confabulation control all sat at 100%. Not general
-degradation — the shape 4-bit input activations produce on the most
-reasoning-dense task. Recorded as CONFOUNDED until this run separates the two.
+Why it was run, and what it actually settled: a 2026-08-24 battery appeared to
+show a large contradiction-detection deficit with CoT off, which had the exact
+shape 4-bit input activations would produce on the most reasoning-dense task.
+The control ran and found activation precision **close to free** — every other
+task identical across the two builds. That quantization result stands.
+
+⚠ The *deficit* it was chasing does not — the benchmark item was ill-posed. See
+"Superseded claims" at the end of this file. The procedure below is kept because
+the flip is a genuinely useful capability, not because the original question was
+sound.
 
 ⚠ **The A16 build ships a STALE CHAT TEMPLATE and the run MUST override it.**
 Verified by hash 2026-08-24: upstream `google/gemma-4-26B-A4B-it` is 390 lines,
@@ -129,3 +134,41 @@ wrong-answer one. `VLLM_USE_V2_MODEL_RUNNER=0` enables
 `thinking_token_budget` and is the first lever to try if a usable thinking seat
 is ever wanted — deliberately **not** applied here, since it costs the faster
 model runner for a mode production does not serve.
+
+## Superseded claims
+
+Following the repo convention for quant work: when a recorded claim turns out
+wrong, it gets a dated row rather than a silent edit, so older notes elsewhere
+stop misleading people.
+
+| date | claim, as recorded | status |
+|---|---|---|
+| 2026-08-24 | "Gemma-4-26B-A4B-it scores 12% on contradiction detection with CoT off, against gen's 81% — the model owns the deficit." | **RETRACTED same day.** The benchmark item was ill-posed: it presented two mutually contradicting statements and asked for "the contradicting statement", but **contradiction is symmetric** — neither was more the contradicting one, and the model consistently named the absolute claim, a defensible reading the labelling scored wrong every time. |
+| 2026-08-24 | "Domain tuning costs 43 points of contradiction detection." | **RETRACTED.** Rested entirely on the same item. On the corrected instrument the effect does not shrink, it **reverses**. |
+| 2026-08-24 | All pre-fix T2 (contradiction) numbers for Gemma-4, MeroMero-v2, `sec` and `gen`. | **VOID.** |
+
+**The tell, worth internalising: the score was BELOW CHANCE.** 12% on a
+five-option task is under the 20% floor. A below-chance score indicts the
+instrument before it indicts the model, and that should be the first reaction
+rather than a late one. Neither side caught it until the individual items were
+read.
+
+A second defect surfaced while fixing the first: all generators shared one RNG,
+so rewriting one task reshuffled every task after it. Each task now seeds from
+its own name.
+
+**What survived, and it is not nothing:** the A16 control result holds —
+activation precision is close to free on this workload, with every other task
+identical across the W4A4 and W4A16 builds. The two staging confounds caught
+before the run (the misnamed A16 repos, the stale chat template) were real and
+independent of the item defect. The corrected picture, CoT off, n=96:
+
+| arm | core | T2 | T6 | median latency |
+|---|---|---|---|---|
+| `char-rp` (Gemma-4) | 92.5% | **94%** | 69% | 0.24s |
+| `sec` | 92.5% | 81% | 81% | 1.11s |
+| `gen` | 86.2% | 50% | 81% | 0.33s |
+
+Gemma leads on the very axis it was suspected of failing. Its actual weak axis
+with thinking off is **T6, spatial composition at 69%** — and an earlier run
+showed CoT-on takes T6 to 100%, which nothing else benched has managed.