Getting in touch with director

An actor has changed his performance for the worse in a climactic scene in a show that is obviously based on something communicated "in passing" that was then misconstrued.Actor took the comment all wrong,changed their first and BEST instinct and now they have RUINED that scene. He almost freezes.Does a person just drop a note in the mail to the director anonymously so he can pass an acting note to his actor?How can you ask a director without causing trouble and ID'ing people to get the actor to change it back? Is it too late? The audience is really missing out. Director may not even notice it. The situation is clumsy. This esteemed actor is not driven by their chops with this change.They changed it for no dramatic reason about 3-4 months into the run.It is an insane personal situation that caused them to alter their performance suddenly after it was "set" and this actor has done it before.Their track record speaks for itself.The audience sometimes loses as he tries to iron out his personal relationships by being so damn eager to please 1 very stage-ignorant person "out there"--during the show!! I think it is too late.They have done no other noticeable altering so it may seem kind of minor at this point, but it is during the most important scene in the play!!! Thanks.

Thanks Stuart.The actor wrongly assumed this change would please me (his little hello to me)and it stops the action dead.The action definitely has morphed and it is pretty unethical and he may not do it every performance, but he definitely alters it.It is not a subtle change to me, but I know what the actor is changing, so not sure if it is noticeable enough for the stage manager to comment on. It may be an inconsistent change. It was based on a recommendation he thought I had, but I didn't know he misinterpreted an otherwise offhand comment I made until it was too late, so it got all messed up. He knows what he is doing and why-and it is wrong.Some might think it hilarious and he has done things like this before (think Carol Burnett and the ear thing-but during the show) as a supposed grand gesture sort of thing but it is disturbing to me, but I have always said nothing becuase he would take it as an insult.It has happened maybe 3-4 times in other productions.I can't tell the actor directly and he isn't to know if I rat him out because then he would be furious. He blows gaskets all the time. I will just let it go... again.Thanks for info tho. I just don't have the energy to deal with it directly.