Rashi on Leviticus 10:20/רש"י על ויקרא י׳:כ׳

1וייטב בעיניו AND IT WAS PLEASING IN HIS EYES — He admitted his error and was not ashamed to do so, by saying (instead of admitting it) “I have not heard a statement (from God regarding this)", but rather he said, “I have heard, but I forgot it” (Sifra, Shemini, Chapter 2 12; Zevachim 101b).