The shit stirring thing always seemed like a possibility to me since about season 2. There is some sort of after-the-episode bit, or a commentary track, where Benioff tells a stupid story about getting tipsy at something like a wrap party for season 1 and where he was sizing up Jason Momoa for God knows what reason. He apparently ended up challenging Jason Momoa to some sort of hand slapping and/or arm punching match. (Like playing “red hands”) Jason Momoa beat the white off him, lol.

It always stood out to me as extremely odd the writers of this show would look at any of their actors and be like, “Oh, how tough could they possibly be?” Even if they were tipsy, the whole tone and the sense of ego was baffling.

Add on top of that the other story mentioned in this thread, regarding them all-but-admitting they were happy to kill off Barristan after the actor pleaded his case to them, and it really does seem like one or both of the two showrunners have a permanent chip on their shoulder of some kind.