This episode was aired out of order, having been filmed as part of the previous season. Clair and Pam are sporting different hairstyles, Rudy, Rudy's friends, and Olivia appear noticeably younger, Sondra and family are not living at the Huxtables' house, and the kitchen has not yet been remodeled. Additionally, Cliff is wearing his "SD" pin, which he wore throughout Season 7.
Sondra drops by to return a book to her mother. According to the time line, they haven't moved into their new house yet and still live in the Huxtable household.
When everyone is sitting down to eat Rudy's friend grabs a piece of chicken. Between shots her plates switches between the chicken and salad even though she did not grab any salad.