Revealing mistake: In the scene where Ellie is testing her Thanksgiving turkey by giving Morgan a piece, when she throws it in the trash he says 'no no no Sarah.. what are you doing!', which is the actor's name (Sarah Lancaster), not her character's. Maybe edited in some versions. (00:09:40)
Factual error: When Chuck and Jill recover Guy LeFleur's hard drive containing the list of Fulcrum agents, General Beckman says that the flash drive is encrypted with a 512 bit AES cypher. She then goes on to state, "the computer is trying every possible key against the encrypted data, " i.e., a brute force hack. However, it would take the fastest supercomputer in the world longer than the existence of the known universe in order to crack even a 128 bit AES encryption (and a 512 bit AES encryption has the number of possible keys of a 128 bit AES encryption, raised to the fourth power). In a previous episode, Chuck refers to the computer in Castle as having a "30 teraflops" speed, which is far less than the current fastest supercomputer. General Beckman instead says it will take only hours or days. (00:26:10)
Plot hole: Casey needs to get Devon's hospital keycard in order to get into the secure holding area to plant the listening device into the pacemaker before it's implanted into the terrorist. They obtain the key-card by stunning him at his bachelor party and see Casey using it to access the storage facility, backed up by Chuck and Agent Forrest. We then see the terrorists scanning their leader and detecting the implanted bug - Devon is listed as the surgeon. Immediately after this, we cut to Devon waking up from his bachelor party with his keycard missing. None of the three agents involved in planting the bug could possibly have handled the operation, no other agents are mentioned as being present and, as the break-in occurred during the daytime, the staff of the busy hospital would have noticed had an unknown surgical team suddenly taking over one of their operating theatres. So Devon apparently got into the hospital with no key and did the operation while completely unconscious.
Continuity mistake: In the scene with Orion working at his computer in Hong Kong and the Fulcrum agent is coming, he is watching Chuck, but he hears them, closes the window and its blank, but then the immediate next shot the screen shows Chuck still, and then the next shot it is black again. (00:02:10)
Continuity mistake: The yellow pen that John Casey stabs into Ty Bennett changes between shots after Ty pulls it out. As he rotates it in front of the camera we can see that the bold BUY MORE logo is only printed once. Still in the very next shot, not only has the text changed direction (reading from the hat-side to the tip-side now), the logo have also appeared in front of Ty. (00:05:50)
Continuity mistake: Sarah is making Chuck a frozen yogurt using a banana and a knife. Take notice when Sarah cuts up the banana, the slices are disorganized while she is talking to Chuck. However, when Sarah decides to pick up the slices of banana, the pieces are now nicely organized.
Continuity mistake: There's a noticeable jump cut after Jill separates from Sarah - we see a cubicle, with a Fulcrum agent getting up and running off to the left, leaving his chair spinning slightly. He exits, then just before Jill enters (apparently in a continuous shot), the chair suddenly rotates to a different position and then stops.
Revealing mistake: When Sarah and the Triad chick are fighting, Sarah is thrown through the window of a late model Dodge. When she is thrown through the window, it breaks into large shards, indicating it is not made of the safety glass which is used in all car windows. But then, while they are fighting in the car, all the glass inside is small pieces of safety glass, not the shards.
Continuity mistake: When Sarah shot the Fulcrum agent and Chuck was looking that moment at his mom's bracelet, she has the bracelet on her left wrist and the red watch on her right. However, when she comes back to Buy More to talk to Chuck and hug him, she has the bracelet on her right wrist and the red watch on her left. Also, the first time Chuck showed her the bracelet, he put the bracelet on her right wrist.