https://huggingface.co/madebyollin/texture-fix-vae-for-qwen-image-2.1

Use this too.

Qwen Image 2.1 is touchy when it comes to getting right sigmas, like really touchy. Sampler/Solver is important too, but sigmas even more.

Issue is that ComfyUI hardcoded one sigma and that aint right and for most optimal results you need original designed floating sigma that depends on image size (I would say image size AND longest side).

If you ask right AI with enough context, its able to fix it. I have solution but I have a lot of other stuff tied to it, so it wouldnt be that easy to publish.