Continuity mistake: When Al Bundy drops the stiletto shoe into the fish tank, he reaches down into the tank to get it and his sleeve and hand are dry as he shows the shoe. Also, hardly any water drips off the shoe. (00:17:00)
Other mistake: When at the gas station, they are out of gas. He doesn't put any gas in but later Peggy starts the car up and drives away.
Continuity mistake: Al and Bud are being hunted because they are the final male Bundys. However, earlier, in Baby Makes Money (Season 4?) Al and Peg went to the funeral Of Al's uncle, Stymie. There were other male Bundys. The heirs had to produce a male heir and name him after Uncle Stymie to get all the inheritance. The 3 England Show episodes all have the premise that Al and Bud are the only male Bundys left.
Visible crew/equipment: When Buck is sitting on the couch before Al and Bud come back, the shadow of the camera boom can be seen moving on the stairs.
Continuity mistake: Steve comes in the back patio door and closes it. When Kelly gives him the house key you can see in the background that the door is open.
Cheese, Cues and Blood - S6-E4
Continuity mistake: When Kelly shakes her head no to the guy she is playing for $10,000, he misses the shot and the ball stops at the far end of the table. When Kelly goes to take the next shot for the win, she is hitting the cue ball from the other side.
Revealing mistake: While they are jousting, there is no one at all next to the stage in the wide shots. Every time they show the stage up close, there are 40-50 people. It changes back and forth the whole scene.
Continuity mistake: At the airport outside, Marcy yells at Jefferson and knees him. While she does that, there is a man wearing a white coat walking behind them. Camera instantly changes and there is no man at all in a white coat. In fact, there is now a woman wearing a white coat.
She's Having My Baby (1) - S6-E1
Continuity mistake: In the prior episode, when Peggy tells Al she is pregnant, Jefferson just smiles at Al after she tells him. In this episode, at the beginning, when Peggy tells Al she is pregnant during the recap, Jefferson smiles at Al but also pats Al on the shoulder.
Plot hole: Outside the Savoy, Marcy tells Jefferson that at last, they found the Bundys. How did they know that the Bundys were there? The Darcys had not been in touch with them since they were left behind at the airport, and the Bundys only decided much later that they were going to the Savoy.
Deliberate mistake: Why would Al have his Polk High football uniform in England?
Suggested correction: Al cherishes his memories as a high school football player. It's quite possible that he takes the uniform with him on some trips, especially when going to another country. I've known people who do this with items that are important to them; i.e. a jewellery box or a favourite picture of family. They feel better keeping the item with them, in case something happens at home while they are away.
Continuity mistake: After Bud's Hail Baby, the spoon that had been to the right of Peggy's glass, changes position.
So This is How Sinatra Felt - S6-E12
Plot hole: Bud and Kelly hide behind the cash register all day. They talk normally the whole time yet Al doesn't hear a word they say and has no idea they are even there.
The Mystery of Skull Island - S6-E14
Continuity mistake: When the grown-ups are playing 'Ethical dilemma' Peggy lands on the field 'Sexual intimacy' (the field right after 'Start' with a one-word-title). Four minutes later in the show Al lands on the same field - but now it's 'Caring'. They can't have turned the game board because all the cards on it are in the same position. (00:09:40 - 00:13:40)