They almost certainly knew...

https://huggingface.co/Qwen/Qwen3.5-0.8B#best-practices

> In thinking mode, we have observed that when using the recommended sampling parameters, Qwen3.5-0.8B is more prone to entering thinking loops compared to other Qwen3.5 models

There's also an active issue tracking this here: http://github.com/nobodywho-ooo/nobodywho/issues/557

Pretty sure that is also why this model was specifically chosen.