Out of Time - S2-E1
Other mistake: Sara tells Jefferson that the professor has a one hell of a right hook (referring to Martin knocking Einstein out). Jefferson replies, "seriously, Gray punched him out?" The subtitles mistakenly say "Ray."
Other mistake: When the 3 go to Ivy Town, "Disco Inferno" is playing. However, this is 1975 and the song was recorded and released in 1976.