Infamous, eh?
Oh yes - extremely infamous. Check out this topic starting with this post:
1970 program announcement
and also be sure to read reply #3 to read specific letters as well as a bonus letter that will give you an image in your head with regard to a certain character - an image that will probably prove to be nearly impossible to get out of your head whenever that character is on screen in upcoming eps.
If this adjusted backstory is the infamous part, well, this had already been introduced into the story earlier.
Given the major promotion for the ep (that's detailed in the linked post), the sore spot with many fans (as is obvious in the letters shared in reply #3 of the linked topic) was the fact that practically everything that was supposedly "revealed" as "the
real story of the terrifying Leviathan plot", including that business with Oberon, was already known.