Evidence record 18254 · automatically gathered

Mismatch Matters: On-Policy Distillation Beyond Token Agreement

On-policy distillation (OPD) has emerged as a core component of modern LLM post-training pipelines, yet we reveal a failure mode: degenerate agreement, where students exploit repetitive loops to achieve near-perfect token agreement with the teacher despite globally flawed responses. We therefore shift our focus from agreement to teacher-student mismatch, and find that mismatch tokens can be mainly categorized into two types: student-excess tokens and student-deficit tokens. Student-excess tokens

Record details

Published: 10 August 2026
Source: arXiv cs.AI
Category: Research
Topics: Regulation · Children & education
Retrieved: 11 August 2026

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ethics.ai (10 August 2026), “Mismatch Matters: On-Policy Distillation Beyond Token Agreement,” evidence record 18254, https://ethics.ai/record/18254 (originally published by arXiv cs.AI).

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