"conditioning memory failed (size of tensor a (492) must match tensor b
(499))" — the compatibility gate checks the channel width and the batch
and deliberately not the sequence length, so the payload passed and the
lerp threw. On LTX the encoder pads to a fixed length and this never
happened; Qwen does not pad, so on H3 the length moves with every prompt
edit and the entire learned direction was dropped for that run.
_resize_conditioning_sequence_like was already in the file for exactly
this, with zero callers. Both the blend and the repel now use it, and say
once when a payload had to be resampled.
An exact-length payload is untouched, so the common case — same prompt,
re-rolled — stays bit-exact.