In minute 11 of this episode, Phoebe comments on Ross' handwriting, claiming that he "let Ben write the envelopes". She shows the envelope to the camera at time stamp 11:05. Then camera pans away to Chandler, who walks into the room. At time stamp 11:20, Phoebe's putting her invitation back into the envelope. The front of the envelope is still facing the camera. However, where's the address gone? It was there 15 seconds ago.. Has it just magically been scrubbed off?