Continuity mistake: After Squad 51 is dispatched to the 'injured man', when Roy and Johnny get out of the squad, Roy is not wearing his watch as they're walking to the victim while getting hounded by the dog, but in the next shot the watch is back on Roy's wrist as the dog chews on his pants.
Continuity mistake: When Fred takes his plate from one room to the next, they switch from a small object on the plate in the living room to a full size Danish when he walks into the kitchen screen.
Continuity mistake: In the first episodes, Col. Blake's wife is named Mildred, later her name is changed to Lorraine. (In case of confusion, when Col. Potter came to the 4077th, his wife was also named Mildred, but that's not relevant).
Continuity mistake: The Gentlemen's and Ladies' Department is on the first, third, or fourth floor of Grace Brothers, depending on the episode.
Continuity mistake: In the opening credits where Bob is on the 'el' platform, the train car he is sitting in is different from the one he enters in the scene before. The car he is shown entering is an older car with small windows and the car he is sitting in is a newer model with much larger windows.
Continuity mistake: Just after Otis makes the ghost sounds from inside the house, it shows the gang standing together outside the house. Otis is with them outside, which is impossible, as he is inside the house pretending to be the ghost.
The Search - S4-E15
Continuity mistake: When John borrows Vern's blue car to search for Olivia and the kids, its license plate number is "45-2678" in wide shots, but when John-Boy spots their truck at the side of the road John stops short, and the license plate number is "84-6209" in the closeup. (00:17:10 - 00:18:45)
Continuity mistake: As Banacek approaches the room in the farmhouse that has the cross, he has a cigar in his mouth. As he enters, the cigar is gone.
Continuity mistake: Towards the end of the episode, Maude makes Walter breakfast and lists some things she will get done around the house. One is to paint the kitchen chairs. She spray paints the chair with Walter in it - the amount of spray paint on Walter's jacket changes thoughout the scene, especially when Maude is on the phone turning down a job.
Continuity mistake: Caine leaps onto a table that has a pitcher on it, which disappears and turns into a small wooden keg that he kicks into the face of the thug fighting him.
Continuity mistake: When Batman and Robin guest star on the show, Batman's cowl changes from covering his neck to exposing his neck.