It takes some contact time to stain. It will stain just about any plastic if it’s in contact long enough. So for things you sanitize and don’t soak you probably won’t see a lot of staining.
I switched to Iodophor after a persistent low grade infection got into my Brew house Fermenters back when I fermented exclusively in plastic. The Iodophor stopped it. Now I’m mostly stainless, but still use Iodophor for everything, except the occasional bottles used for competitions (fearing a highly sensitive palate might pick up any trace of Iodophor in a light lager or blonde ale. (I know - it is more superstition than likelihood, but I enter so few competitions anymore that I guess I am hoping for a slight bit of luck).