"By this time, I had some sense of the plot [of Jean-Luc Godard's 'King Lear']... The narrative was now roughly this: The world has been destroyed, post-Chernobyl..."

"... and a puckish little man named William Shakespeare Jr. The Fifth is tasked with re-creating his famous ancestor’s work. The avant-garde opera director Peter Sellars was cast as Shakespeare’s descendant, and Godard inserted himself in a role that doesn’t appear in any Shakespeare play: Herr Doktor Pluggy—an inventor who wears a contraption on his head, with cables dangling, doing research in pursuit of something called 'the image.'.... One day, Godard sneaked into [the room of the actor playing King Lear, Burgess Meredith] and short-sheeted his bed. I noticed that the director seemed to derive satisfaction from provoking people... Toward the end of the shoot, Godard mentioned that he deemed everything I did in the film completely authentic except for one moment.... I asked him which one. 'I’ll tell you when it’s over,' he said.... When I finished my scenes, I approached him to ask which moment, and he told me that it was the scene in which Cordelia lies next to her father, dead. This was completely nonsensical, since it was the last scene that I filmed—it hadn’t even been shot when he made the comment."

Writes Molly Ringwald, in "Shooting Shakespeare with Jean-Luc Godard/The actress and writer recalls working with French cinema’s enfant terrible" (The New Yorker).

What sort of person goes in for practical jokes? I mean, someone who's not in the comedy field — a serious, accomplished person: Why would he favor that particular way of fun? It's one thing to devise something original, but to do a standard practical joke like short-sheeting the bed: Who does that?

Ringwald said Godard "sequestered himself from everyone" and, she thinks, "he was actually a bit shy, trapped in his mind. Perhaps the only way he could make sense of anything was to film and edit it."

How does that square with short-sheeting the bed?  

As for the remark about inauthenticity, I see a subtle humor there. Wasn't he saying, essentially, you were perfect? The only time she was inauthentic was when she, a living person, had to play the role of a dead body. Yes, the dead-body impersonation hadn't happened yet when he made the remark, but he knew she would play that part and he must have considered it funny to unsettle her as he set up a punchline that would make sense at some point in the future.