The Return of Malcolm Merriweather - S4-E28
Corrected entry: As Andy walks in the house with Malcolm and greets Aunt Bee, he asks her, "You remember Malcolm don't you?" She replies that she does. This is not possible because in the other episode he appeared in, "Andy and the English Valet", Aunt Bee left town to care for a sick cousin and never met him.
Correction: Malcolm and Aunt Bee met briefly as Malcolm was leaving the Taylor household and she said he should speak English because she couldn't understand him and Andy replied that he was.