During the ice cream scene with Rachel, Monica, and Chandler, the ice cream container that Chandler is eating out of rotates in his hand, showing different parts of the container. Moreover, two different containers of two different, but similar, colors were used for the filming of this scene.
When Ross ate a pie Monica made previously he had a reaction as he is allergic to kiwi,however this time he drinks Monica's juice which is kiwi strawberry and doesn't have an allergic reaction.
Phoebe tells Joey that he didn't get a part because he has a terrible Italian accent. But later in The One Where Ross Can't Flirt (1999), he speaks Italian just fine, and he clearly always has, because he is communicating with his grandmother who doesn't speak English.
Joey wouldn't be able to audition for the roles Phoebe got for him because of his injury.