Not Without My Daughter - S1-E21
Audio problem: In the final scenes where Tobias is shooting at the rats you see the shot blasts after each firing of the gun. On the fourth shot there is no visible blast but there is still an audible gunshot when it happens.
The One Where They Build a House - S2-E2
Revealing mistake: When Michael is talking to George Michael, Oscar, Buster, and Tom Jane about the house they are about to build (and what they all want out of it), it is clear in the wide shots showing all five that Tom Jane is not present; the person standing in for him has a completely different haircut and wears glasses. They try to hide it but it is obvious at several points. (00:14:15)
Continuity mistake: In the scene where Michael has just taken Lucille number two to Tobias' new club, the shots are obviously taken on different occasions. The collar of his jacket goes from misaligned to correct, his hair goes from ruffed to "done" and the lighting goes from hard and sharp to soft. (00:18:50)
Audio problem: When Michael is walking into the hospital room, he says "Where's the baby?" to Maggie. However, his lips do not match up with the word "baby", and it appears he is saying something else that is not heard. (00:19:00)
Visible crew/equipment: During the "On The Next" segment at the end of the episode, Buster has replaced his hook with Franklin the Puppet. While Franklin speaks, a camera man is seen on the right.
Continuity mistake: When Michael runs into Barry in Reno, the envelope Barry is holding (containing money and a passport for George, Sr.) changes from a manila color to plain white. (00:14:15)
Visible crew/equipment: After Bob Loblaw suggests there may be a spy who is listening on secret information, the camera cuts quickly to everybody in the room individually before doing a wider shot. In this final shot, a boom mic is visible and is seen for about a second before being pulled out of frame.
Suggested correction: This is a well-know intentional joke in the show, relating to the fact they were being recorded.
Continuity mistake: Several episodes in season 4 have scenes that take place immediately after the events of the final episode of season 3. However, the 7 years that passed in real life between seasons 3 and 4 are made apparent by the appearance of some characters. Notably Michael Cera and Alia Shawkat who had visibly matured out of their teenage years, and Portia de Rossi, who had plastic surgery on her face.
Continuity mistake: In the security room, in shots from the back of Ron Howard the apron strap is on his neck, above his shirt collar. In shots from the front, and when he turns, the strap is lying directly on his collar.