I believe it is because GLM 5.2 has extra anti-cyber training instilled in it. Similar to Kimi k2.7 code.

Deepseek v4 pro being in preview with less "safety" training makes it stronger for that reason. Thinking will be different and in the end, it will actually try to be useful. Just expect future Chinese LLMs to further push out "safety" guided LLMs. The future is bleak for open weight models. Prepare to have "guidelines" enforced unceremoniously to all.