Archie brings up when he and Edith's cat Arthur had kittens, and they refer to Arthur as "she" and "her." However, in previous episodes, Arthur was always referred to as a male cat. Archie even once said "I hated his fish-eatin' guts."
Archie says that for the first time in six years he shook Mike's hand, but he's forgetting about in the previous season he did shake hands with him when they made the bet in the episode, "No Smoking". They also shook hands when they first met each other in "Flashback Mike Meets Archie".