Plot hole: In "Into Hell, Part 1", season 4, episode 7, the Unit discovers a soldier who they think is Betsy, tied to a chair. They note that the room is covered with PIRs or Passive Infrared Sensors. They then take out their night-vision goggles and begin counting the number of "infrared lines" they see. However, PIR sensors don't emit anything; they are passive.
Other mistake: At about the 8 minute mark SnakeDoctor is talking on the radio to Bushmaster who is on the ground. There is a few seconds long shot where Bushmaster's earpiece is dangling wires and not connected to his Comms Gear on his vest. That earpiece can't be wireless.
Continuity mistake: Betsy rappels/climbs "first hand" because of a rope that seems to be anchored from the top, and is in a climbing brake or figure 8 rappelling device thus descending below her. But then it's visible that she's top secured by a knot, and when she sits, the rope is being recalled.
xx:xx:xxMarcus DH Ghavidel
Factual error: When the American team almost assassinates the vice-chancellor in the beginning, the German team comes in guns blazing. No special forces unit in the world would do that. They would have suppressed weapons, and use their ammunition diligently.
Continuity mistake: As stated in another entry, Brown states that they are in a Huey when they are actually shown in a JetRanger. Later on, after twice showing night shots of a JetRanger flying overhead, they are shown in the cargo area of a Huey, then are shown flying and deploying out of a Huey.