Sheldon returns Amy's scarf which she says that she wore the night she went ice-skating but in The Space Probe Disintegration Amy explains that she cannot go ice-skating because she has unnaturally brittle ankles.
As in the previous episode, Penny wears her hair pulled back. This may be to draw attention away from the fact that her hair is significantly longer than during the Vegas wedding, only days earlier in the show's time line.
Penny says that she never thought Leonard would be capable of kissing someone else while in a relationship. However in The Good Guy Fluctuation Leonard goes to Penny for advice after kissing a girl despite being in a relationship with Priya.
When returning the box with Amy's items Sheldon knocks only one time to gain entrance more easily. When Sheldon leaves he knocks three times on the table. In line with his character he should only have knocked two times to complete the three.
During the "Fun with Flags" web show, Sheldon passive-aggressively makes a reference to Amy's "genitalia". However, at this time in the series, Sheldon and Amy had not had sex.