The incremental per-component cache built and cached all components correctly, but
generation then failed:

  RuntimeError: Expected all tensors to be on the same device, but got index is on
  cuda:0, different from other tensors on cpu (... wrapper_CUDA__index_select)

Cause: the load used the `balanced` (device_map) strategy. accelerate's device_map
only dispatches components it LOADS — injected pre-loaded components keep whatever
device they're on (CPU) with NO offload hook, so a forward pass mixes cuda inputs
with cpu weights.

Fix: when incremental cached components are injected, force a HOOK-based offload
(model → group → sequential), which add offload hooks to EVERY component in the
pipeline (injected included). model CPU offload keeps only the active ~7 GB 4-bit
expert resident, so it fits easily and is fast. device_map strategies
(balanced/disk) are skipped in this case.

Safety net: a non-OOM generation failure that looks like a device mismatch now
retries ONCE with the incremental cache disabled (plain build = pre-cache
behaviour), so generation self-heals even if the injection path is imperfect
instead of wedging the queue. (Load-time failures already fall back this way.)
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01RdMufYvtTbtGDWsiZVoXce