Wrong img2img behaviour

[lbosk]

Load an image
Select the following options:
Control Type - none
Denoise - 0 (or 0.01 beacuse, according to the API, 0 is not allowed)
model - stable_diffusion
Steps - 1
Upscalers - RealESRGAN_x4plus

You would expect to receive the same image, just twice the dimensions (and this is what you get using tha API), instead you get a simple noise.