M-shape test loss

<img width="3072" height="1582" alt="Image" src="https://github.com/user-attachments/assets/638f20a9-e65c-4e80-95a8-c7f783e9c866" />

## Problem description

There is a M shape for test loss

## How to reproduce

1. open comfyResearch: https://online.comfy-research.com/
2. Type in 嘿嘿 in the input field
3. draw the random graph and run