Guess Who's Coming to Breakfast, Lunch and Dinner - S10-E1
Revealing mistake: Near the beginning when Al is looking for his magazines under Bud's bed, a large shadow of someone crosses over him showing someone in production crossed in front of the lighting.
Requiem for a Dead Briard - S10-E3
Continuity mistake: When Peg is comforting Kelly about Buck passing away, she is holding a bag that says "Petropolitan" on the front. The next shot when they go back to her, all a sudden the words are gone from the bag she is holding and Bud is holding a bag with those words.
Flight of the Bumblebee - S10-E7
Continuity mistake: Jefferson mentions having Thanksgiving dinner at Marcy's father's house. Yet, in the pilot, it's mentioned he's dead, as well as her two stepfathers.
Revealing mistake: When they blow up the scoreboard at first in slow motion, the entire scoreboard is blown up and destroyed. The next shot only a small portion at the top and middle is destroyed, not the entire thing.
I Can't Believe It's Butter - S10-E13
Revealing mistake: When Griff drinks the gravy right before calling "Butter", his glass is empty.
I Can't Believe It's Butter - S10-E13
Plot hole: Griff doesn't know Peg's mom is Butter. He comes to Al's wanting to meet her. Al gathers the family to talk about what to do. They say Griff can't know its Peg's mom, yet they talk out loud and Griff is standing right there while they are sitting at the kitchen table. It's not until the end of the episode he finds out.
The Hood, the Bud and the Kelly (2) - S10-E15
Revealing mistake: Whenever Al or Jefferson falls off the roof you can plainly see it's a dummy wearing their outfits.
Character mistake: When Bud is showing Al his school project of a fan page turner, he has it on the left side and blowing the pages left to right. That would be blowing the pages the wrong direction to flip pages. It should be on the right side changing pages right to left.
Continuity mistake: Al enters the house at 3am with Lucky. It is sleeting outside and there is snow all over the front and backyard. Later that day, Al is in the backyard, no snow to be seen, and grass and bushes in full bloom.
Continuity mistake: In this episode Al is building a dog house for Lucky. In Season 9 episode User Friendly, we are shown that there already is a dog house, which has electricity and a light.
Factual error: Griff's shown being strapped into the electric chair. Problem is Illinois had stopped using the electric chair and switched over to lethal injection in 1983.
Answer: It was one of the hoses connected to the engine, nothing specific, but to indicate that Al tampered with the vehicle.