Visible crew/equipment: S4xE8 "Meet Kevin Johnson": Near the end, Karl has nothing in his left ear when he and Alex sit down and start talking, but when Karl falls onto the ground, the actor has a wireless earwig device in his left ear in his close-up, before Alex turns him over. Then, when Alex sits by the tree distraught, Danielle tries to convince her to listen, and in Alex's extreme close-ups, she has a mini lav mic (similar style to DK3 series) at her right ear that becomes visible.
Continuity mistake: S4xE8 "Meet Kevin Johnson": Near the end, Danielle, Alex, and Karl stop for a couple of minutes to drink water, and when the bullet hits Karl's water bottle, in the close-up we see the low level of water inside the water bottle directly above the leak, but in the next shot there's much more water inside the bottle above the leak.
Something Nice Back Home - S4-E10
Continuity mistake: At the start, Jack pops a bottle of pills, and the orange bottle is in his right hand. The camera cuts, and now the orange bottle is in his left hand. (00:01:30)
Cabin Fever - S4-E11
Continuity mistake: In the scene just after John Locke's teenage mother runs from the hospital room, the nurse converses with the grandmother. You can see her put a cigarette to her mouth with visible lipstick stains on the wrong end of the cigarette, possibly from previous takes. (00:32:10)
Answer: He was eating a peice of an orange with the skin still on.
XIII