Season 1 - The end of the episode where Gomer has to deal with a bully.

EDIT: the name of the episode is literally "Gomer Learns a Bully" 🤦 https://m.imdb.com/title/tt0589954/

I expect the use of "learns" in this case is to mimic how Gomer would have used the word, which reflects his "backwoods / country" origins. Perhaps it was meant to highlight his supposedly simple nature and how he yet managed to solve the problem.