Two things, both from the same debugging session.
v2a_grad_scale is JoyAI's coupling knob and is never installed without
joyai_audio_memory (see the call site), so a left-over value with the feature
off was being reported as an H3 limitation — blaming the model for a knob that
would be equally inert on LTX. Both the sampler's pre-run notice and the
Editor's inert-setting hint now gate on joyai_audio_memory.
The NaN guard only saw the sampler's OUTPUT, which cannot tell "the model
computed garbage" from "the model was handed garbage and propagated it" — and
those have disjoint suspect lists. _sample_chunk now checks the incoming latent
and the schedule first, and says which it was. The schedule check is there
because it is hand-typed and our solvers divide by sigma (er = sigma_next /
sigma): an interior zero or a repeated value is an instant Inf that poisons
every value downstream. A trailing zero stays legal — it is only ever a step's
target, never a divisor.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
