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Apparatus

SPORC as the interim target

Research Computing retired rc-onboard for research jobs on 2026-09-16, and fl-mlm has no TIGRIS association: in ColdFront both fl-mlm and prdiscourse carry Needs Review, and the RC documentation grants every project without a pending review a TIGRIS Slurm account. sacctmgr show assoc lists fl-mlm on sporc only, and sbatch --test-only against the tigris partition fails with Invalid account or account/partition combination.

The cohort-trend worry, tested properly

scripts/quasi_independence.py, datasets/results/quasi-independence.json. Lynden-Bell needs the lag and its truncation limit to be quasi-independent, and the limit here is a deterministic function of creation month, so the assumption is that review latency is stationary over the eighteen months the corpus spans. The log recorded that it fails, citing OpenStack's P(lag<=1) rising from 0.667 in the oldest cohort to 0.905 in a recent one. That citation was wrong, and the conclusion drawn from it was too strong.

The temporal probe is weaker than the design assumed

Zhang et al., Test of Time: Rethinking Temporal Signal of Benchmark Contamination (arXiv:2509.00072, ACL 2026), argue that post-cutoff performance decay, the signal the time-partition probe reads, is not dependable evidence of contamination. Their result is that the construction of the items distorts the temporal pattern independently of the source material: model-transformed questions and cloze questions drawn from the very same documents produce markedly different temporal signals.

What the base model's own report says about its training data

The contamination battery compares a post-cutoff window against a pre-cutoff control, so the cutoff is load-bearing and had never been sourced. Search returns "June 2024" for Qwen2.5-Coder with some confidence. It does not survive the primary source: in QwenLM/Qwen3 discussion 1093 a user asks whether the cutoff is June 2024, a maintainer pings two team members, neither answers, and a third participant offers June as a personal opinion. No Qwen maintainer states a date. It is a community guess with a citation-shaped shadow, and the battery must not rest on it.

PILOT RERUN: the number to quote

Job 143893, same registered model and budget, with every confound the review found removed: deduplicated first (174 of 201 kept), prompt through render_chat for training and both arms, every training example seen exactly twice, LoRA init seeded before attachment. Change-grouped split: 88 changes to 70 train / 18 held out, 147 / 27 examples, 0 of 27 held-out examples repeating a training pair.

transformers 5 removed warmup_ratio

TrainingArguments keeps only warmup_steps. The declared budget keeps the ratio, because it is scale-invariant and pinning steps would mean a change in corpus size silently changed the warmup fraction on a pre-registered parameter. training.warmup_steps derives the step count at construction.