I think it's important to keep this in the top-of-mind. For me, it's too soon to tell "who's sayin' what."
Which, buy the way, isn't to say that Nunes doesn't want to hold Sessions in contempt.
In the movie, Sessions and Mueller are characters upon which plot twists are built. Lots of activity and discussion surround them, but the story-line hasn't yet revealed their motives or deeds.
At this point I'm whispering, "why do you think they did that?"
Waiting for the 3rd act twist...
Just keep watching as things go upside down and twist left to right.