[simone-chen]

• Native vLLM MoE layers can retain expert weights through bound-loader reference cycles after a collection callback returns. A paired B200 experiment reproduced accumulation through three original callbacks and an OOM on the fourth; post-return collection released each layer and completed all four full token sweeps.
• Collect unreachable cycles once after a successful run_moe_torch return. Keep the native callback body, token sweep, timing, dispatch, case keys, exception propagation and multiprocessing callback identity unchanged.
• Validate with 83 focused CPU tests covering cycle release, callback boundaries, failure propagation, argument forwarding, pickle identity, import compatibility and getter/EP contracts; Ruff and diff checks pass. Production GPU smoke remains pending on the separate pinned campaign source.
• Stacked draft dependency: fix: preserve native MoE activation and routing contracts #589 at d67e3ce06fc27c1e7cb6c308c9ee5f2f103fc501. This PR adds only the cleanup, its tests and collector documentation. Retarget/rebase onto main after the dependency lands; do not merge into the component branch as campaign publication.
• The source closure changes. Existing checkpoint loading alone is not permission to reuse old measurements; preserve their provenance and qualify the fresh four-callback smoke before continuation. Llama4 EP2 failures remain separate.

[coderabbitai]

Important

Draft PR not reviewed

Draft PRs are not automatically reviewed by default.

• Trigger a manual review

To automatically review draft PRs, update your CodeRabbit configuration:

reviews:
  auto_review:
    drafts: true

• Autofix · Keep fixing CodeRabbit findings and required CI, and resolving merge conflicts

_{Comment @coderabbitai help to get the list of available commands.}

[simone-chen]

/ok to test e505429

[simone-chen]

Superseded by consolidated recurrent/MoE compatibility PR #605, stacked on attention #604. The MoE cleanup is preserved once, including the duplicate in #603. Communication remains #591. Original branches and campaign commit references are preserved; closing without merging.