The Stability Gap: Why Top-K Routing Breaks RL Optimization

Citation @online { li-2025-topk-stability , title = {The Stability Gap: Why Top-K Routing Breaks {RL} Optimization} , author = {Li, Yingru} , year = {2025} , month = dec , url = {https://richardli.xyz/post/topk-routing-stability-gap/} } The Problem Training Mixture of Experts (MoE) language models with Reinforcement Learning can be unstable. While dense LLMs have continuous and differentiable…