Both rungs now sit on the same unwrapped corpus with seed, steps and token count
held, so carrier size is the only difference and the effect is attributable:
held-out 3.329 at 0.6B against 3.018 at 1.7B, a gap of 0.311 nats. The chained
0.6B rerun closed the confound the unwrap opened.
Two things in those numbers need stating or they will be misread.
First, the original wrapped-corpus 0.6B reached 3.172, which looks better than the
unwrapped 0.6B's 3.329 and is not. Different corpus means a different held-out
set, and the wrapped version's 5.7% newline tokens are near-deterministic after a
70-character line, so they deflate the loss with cheap wins. Removing them removed
the easy tokens. It is a measurement artifact, not a regression.
Second, a correction to my own earlier claim: I twice described the 0.6B run as
still descending and undertrained at 3.172. Its series reads 3.176, 3.173, 3.172,
3.172 -- it flattened. All three runs plateau, so one epoch is about right for
this corpus rather than short.
The three-way booth puts 1.7B base, 1.7B tuned and 0.6B tuned side by side on the
same nine prompts and seeds. The base arm is the control that matters: curly
quotes go 0 of 18 on 1.7B base to 15 of 18 on 1.7B tuned, and worksheet-or-
explainer collapse goes 3 of 18 to 0 of 18, so the shift is the adapter rather
than the larger carrier. Hard-wrapping fell from 0.85 to 0.18, confirming the
corpus unwrap carried through into the adapter.
Sense partially returned. The 1.7B arm produces locally coherent sequential
Victorian prose where the 0.6B produced word salad, but scene-level continuity
still breaks mid-passage.
One observation held loosely: curly quotes are slightly lower at 1.7B than 0.6B,
which would fit a bigger model's stronger priors resisting the adapter at the same
rank. That is untested and is not offered as established.
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