The new Firefly 3 model consistently ignores the "Art" setting when rendering people, regardless of other settings. Even when I have simple art settings like "layered paper" selected, the model consistenly renders photorealistic people - even on simple digital backgrounds.
The only way I can find to avoid this bug is to add an instruciton like "simple drawing," or "sketch" to the prompt, which often results in ultra-simplistic results.
I did not have this problem with the firefly 2 model, so I am regularly switching back to that model to render images.