Michael: "Happened before the murder"

S05E06 opens to the family mistakenly throwing Barry a welcome home Buster party after bailing out Barry under the impression the money was for buster. Barry asks what buster is in trouble for, "Murder? Manslaughter?" to which Michael replies "No there's no murder he just tampered with some evidence when Lucille 2 went missing".

Minutes later after Michael, talking about the film project with Ron Howard says, "Is that [ project ] not grandfathered in? Because that happened before the murder."

I don't think that Michael the character is making a callback ( joke ) the the first scene mentioning murder in this episode. Why does he say this? Until this point in the season no one has actually said she has been murdered.

On top of all this David Cross was complaining about scripts constantly getting changed by the hour during shooting causing scenes to be done incorrectly. Was this a mistake? What's going on here?