The NextN/EAGLE draft runs under speculative_moe_backend_context -> MOE_RUNNER_BACKEND=AUTO (trtllm is
forbidden as a speculative backend), so its NVFP4 MoE takes the plain-FusedMoE 'else' branch of
process_weights_after_loading. That branch left w13_input_scale/w2_input_scale GLOBAL (num_experts=256,
they are tagged _sglang_require_global_experts at load) while w13_weight_scale_2 is EP-local (64) ->
_compute_gemm1_alphas did 256*64 -> RuntimeError. trtllm/cutlass collapse to a scalar and cutedsl already
slices; the else/triton path was a latent EP>1 NVFP4 bug. Slice the global input scales to this rank's
local experts (mirrors the cutedsl _slice_scale). No-op for moe_ep_size==1; main model unaffected
(never takes this branch). opus-diagnosed.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
leavelet
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