CP draft shared-KV target prefill only needs the CP-local draft hidden side channel until draft prefill consumes it. The reused ModelWorkerBatch was left with capture_draft_hidden_states enabled, and LogitsProcessorOutput retained the extra draft_hidden_states tensor past that point. Restore the capture flags after target prefill, disable draft-hidden capture for draft prefill, and drop the consumed reference.
Constraint: Large CP prefill batches are memory-sensitive; an extra hidden tensor held across the speculative step materially increases peak memory.
Rejected: Leave capture_draft_hidden_states sticky across draft prefill | it can capture or retain hidden state outside the target-side CP-local side channel.
Confidence: high
Scope-risk: narrow
Directive: Keep CP-local draft hidden as a target-prefill-only side channel unless the draft worker explicitly owns a new lifetime contract.
Tested: g0034 cjy-glm5-new PYTHONPATH=python python -m pytest -q test/registered/unit/mem_cache/test_cp_shared_kv_runtime.py::TestCpSharedKVRuntimeHelpers::test_token_slot_remap_cache_distinguishes_same_storage_views test/registered/unit/mem_cache/test_cp_shared_kv_runtime.py::TestCpSharedKVRuntimeHelpers::test_paged_slot_remap_cache_distinguishes_same_storage_views test/registered/unit/speculative/test_eagle_worker_v2_cp_hidden.py
Not-tested: full speculative integration/E2E workload.
(cherry picked from commit f31ef2293ce0cdda2359a5f4713996d78b47f9df)
EAGLE verification can pass torch scalar tensors through the speculative tree traversal before calling grammar backends. xgrammar/tvm_ffi requires Python int token ids, so normalize traversal indices and draft token ids at the boundary while leaving tensor storage unchanged.
Constraint: xgrammar/tvm_ffi rejects torch scalar tensors for GrammarMatcher.accept_token
Rejected: Coerce tokens inside every grammar backend | the invalid value originates in speculative traversal and should be fixed before backend dispatch
Confidence: high
Scope-risk: narrow
Directive: Keep grammar backend calls scalar-Python typed; do not pass torch scalar tensors through accept_token
Tested: remote g0034 cjy-glm5-new PYTHONPATH=python python -m pytest -q test/registered/unit/speculative/test_spec_utils.py test/registered/unit/configs/test_nsa_index_layers.py test/registered/unit/models/test_deepseek_index_skip_weight_loading.py -> 19 passed
Tested: remote g0034 cjy-glm5-new py_compile for modified runtime files
Not-tested: live decode replay after this commit
