I've seen this on Amazon (but in English :) ) with my actual browsers if I have an ad blocker installed and not disabled for Amazon. perhaps this is carrying over to streamfab if you have an adblocker installed
potenial_user
Never encountered that one in Firefox, i use uBlock Origin.
But how ever i had to do some changes in my NoScript before Prime Video worked properly, because of some scripts that it blocked, they are called:
primevideo.com, amazon.com, media-amazon.com and ssl-images-amazon.com
I do also get a standard Cookie warning from them in Firefox each time i visit Prime Video, but there i just choose to allow all of them.