Saavik falls asleep

[Maurice]

He said it in an article/interview in Starlog magazine. And he probably did that TNG episode because it was a different character and not David Marcus.

Thanks.

Starlog 95, p.28.

When actor Merritt Butrick first learned that his character, David Marcus, would die at the hands of a vicious Klingon in Star Trek III: The Search for Spock, he was relieved. Although scores of Star Trek fans mourned the death of Admiral Kirk's scientist son, Butrick wasn't one of them.
"It did not disturb me that the character died," says Butrick of his short stint as David Marcus in the last two Star Trek adventures. "I did not want to grow up as the son of Shatner. My name is Merritt Butrick and I have my own career. I didn't particularly want to do Star Trek for the rest of my life."

And p.72.

His character's untimely death doesn't mean Butrick will abandon Trek fandom. His relief with David's passing has more to do with the actor's fear of potential typecasting. "To outlive David Marcus has been a test," he confesses. "It's very easy to be typecast because an actor doesn't get fame and recognition doing science-fiction movies, regardless of their following and monetary potential.

In the same interview, he claims they were writing III while shooting II, which is rubbish.