# Q2 v1: Qwen-Image-2512 morphology gate

> **Post-hoc invalidation (2026-08-27):** the training corpus contained fields from all three M1 held-out slides because malformed exclusion identifiers bypassed literal matching. Held-out metrics and checkpoint-selection conclusions in this historical report are invalid. See `reports/SLIDE_SPLIT_AUDIT_REPORT.md`.

Date: 2026-08-26 UTC
Run: `20260826T003100Z-lora-train`
Code: `4d54800ba827ae7744c460166b7d105ed9e12562`
Result: **FAIL — partial tissue improvement and privacy pass, but no checkpoint passes aggregate clinical-fidelity review**

## Purpose and frozen protocol

Q2 v1 tested whether the accepted, slide-disjoint HiESD corpus v2 could move the pinned Qwen-Image-2512 prior toward gastric H&E morphology. The preregistered run used 128 balanced 1024×1024 fields at 0.25 µm/pixel, 32 per category, fourteen non-held-out source slides, NF4 transformer training, rank-32 LoRA, learning rate `1e-4`, one dataset repeat, and four epochs. Every epoch checkpoint was evaluated using the same four prompts and seeds. Checkpoints were accepted or rejected as whole units; cells were never mixed across epochs.

The corpus metadata SHA-256 was `4e475c7d260b023d9b25cc0b6f17d8899fe753ac776d4416e667d979b4cbf8c7`; the v2 provenance SHA-256 was `835f4401d31f6f5cde98c3bc452482b76dc273fb13b45338c4ff975f3a44fce4`. Corpus v1 remained prohibited and was not present in the run.

## Mechanical and reproducibility results

- The immutable remote input gate passed: 128 images, fourteen permitted slides, 32 images per category, exact pinned metadata and provenance hashes, and all held-out slide IDs absent.
- Split preprocessing created 128 cached feature files. Transformer-only NF4 training completed all 512 exposure steps and saved four checkpoints.
- The worker ran from `2026-08-26T00:31:00Z` to `01:13:48Z`, or 2,568 seconds.
- The A100 instance was active for 3,365.826 seconds including startup and automatic shutdown. At the conservative previously recorded on-demand list rate of US$3.673385/hour, that is at most US$3.44 before credits and tax; the actual worker was Spot. The bounded CPU recovery worker ran for 2,044.018 seconds. Including short-lived recovery compute and storage, Q2 v1 is conservatively below US$3.60.
- `QWEN_LORA_COMPLETE` is present and `exit_code.txt` is `0`.
- All 166 files listed by `ALL_SHA256SUMS` independently matched after retrieval.
- All four 472,047,184-byte LoRA checkpoints matched `lora_checkpoints.sha256`:

| Epoch | SHA-256 |
| ---: | --- |
| 0 | `0d686996dd6e3399c67faf71b996b31893469c07a90afb842cbf99446a2e456f` |
| 1 | `0287204713099c9d59af636ad8d5f72617961494cc21a20a0fa48e207cf3541e` |
| 2 | `db1c16af5753bb9a6ead29fe8f92084df19374097c5ebd31738564f4a8930b75` |
| 3 | `557786f2aaa2057db1374224134989fb751d5f3f48a9c036891cab23e17b11b0` |

- All sixteen validation outputs decoded as 1024×1024, 8-bit RGB, non-interlaced PNGs and matched the per-run hashes.
- The A100 and bounded CPU recovery worker are stopped. The original stopped Qwen disk remains the reproducible model/cache source.

## Privacy triage

All sixteen validation images were screened against all 128 training fields using exact RGB equality, 64-bit difference hash, and the pinned non-generative DINOv2-base evaluator at revision `f9e44c814b77203eaa57a6bdbbd535f21ede1415`.

- Exact matches: 0.
- Maximum DINO cosine similarity: 0.943365.
- Minimum dHash Hamming distance: 19.
- Fail thresholds: cosine at least 0.995 or dHash distance at most 4.
- Result: **PASS**, with no flagged candidate.

The privacy report SHA-256 is `34d3881247dd44ace7d6f471a379394f7d5482879944d21650eaaba3a4975eb0`.

## Morphology audit

The held-out-reference/Q0/Q2 sheet has SHA-256 `474c036bd21b891c1f7e0390231ad696bba5b579fad139aaf3496095e13b8a74`. Engineering review found a real and useful shift away from Q0's wood-grain texture:

- Epochs 1–3 produced more gland-like gastric tissue in the normal and intestinal-metaplasia cells.
- A DINOv2 feature comparison against the four held-out fields rose from a Q0 mean nearest-reference cosine of 0.7602 to 0.9170 at epoch 1. This is an out-of-domain engineering diagnostic, not a clinical metric.
- The H. pylori-gastritis and mixed cells retained conspicuous dark curved rods that are grossly oversized and poorly localised relative to the expected 10–20-pixel organism length at 0.25 µm/pixel.
- Epoch 2 suppressed some of the largest curves but did not establish credible organism morphology or convincing aggregate category fidelity.
- No single epoch simultaneously passed normal architecture, gastritis, metaplasia, mixed-lesion, and organism-scale review. Selecting different cells from different epochs would violate the preregistered aggregate checkpoint rule.

The held-out feature diagnostic SHA-256 is `93fe1178ca353bd115d6efdfb8eaf51e931e3817a53b64e4955aeb7533f789d0`.

## Gate decision

Q2 v1 passes training, artifact-integrity, mechanical-output, and privacy gates, and it demonstrates that the LoRA can materially alter the tissue prior. It fails the aggregate morphology gate because the positive categories learn a visually dominant curved-organism shortcut rather than clinically plausible H. pylori scale and localisation. Every Q2 v1 checkpoint is rejected for candidate production. Do not begin Q3 or assemble submission images from this run.

The next technical work remains inside Q2: remove the failed organism shortcut from the training design, preregister a bounded correction or ablation, and require another equal-cell aggregate gate. Clinical sign-off remains mandatory before any final set can be frozen.