65th Academy Awards
There was a minor controversy when Snow White (Disney character) was presenting an award for Best Animated Short Subject. She was voiced by Mary Kay Bergman, Adriana Caselotti, the original voice of Snow White was not aware of this. She was reportedly offended that Disney didn't ask her to voice Snow White during the ceremony.
Mel Blanc
In Disney's "Pinocchio", Blanc was hired to perform the voice of Gideon the Cat. However, Gideon eventually was decided to be a mute character (similar to Dopey from "Snow White and the Seven Dwarfs"), so all of Blanc's recorded dialogue was deleted except for a solitary hiccup, which was heard three times in the finished film.