Continuity mistake: While Hank, Peggy, and Bobby are asking for help picking up the papers with the dangerous ammonia and bleach recipe, a person in back of the group they are talking to that was originally wearing a dark red hat, red shirt, and blond hair switches to a pink, light blue shirt, and brown hair. A window also suddenly appears behind this individual, where there wasn't one before. (00:17:49 - 00:18:11)
Plot hole: In this episode, Hank meets his paternal half brother. They look alike. However, we saw in an earlier episode that Hank's facial structure takes after his mother, not his father. Since they are paternal half brothers, then the Japanese brother cannot look like Hank since he has a different mother.
Deliberate mistake: Hank only discovers the tattoo on the back of his head after having his hair shaved off. There is no way, however, he wouldn't have noticed it before this. The tattoo artist had to shave hair off the back of his head before putting on the tattoo. While he might have not realised right away, the pain the following day and the fact that he would have noticed a large part of his hair missing would make it unavoidable.
Continuity mistake: Peggy Hill's mother seems to change over the course of the show. Prior to the ninth season, whenever Peggy's mother is seen (in the present or in flashbacks), she is portrayed as an older version of Peggy. In the ninth season's premiere episode, Peggy's mother is a lean, leather-skinned rancher who disdains Peggy and lives on a secluded ranch. The change in facial features and appearance is too much to just be a change in style as well.
Plot hole: As the guys are checking out the vacant house inside, they are surprised to see it has a pool. However the problem with this is its right next to the driveway in the front of the house, in the open with no fence in front of the driveway so it would provide a clear look through from the alley. As they state they never noticed it in 18 years living there, yet walking up and down the alley it's a bit hard to imagine being that open and they never saw it. Even the final shot (aerial shot) at the end of the episode we see it was far too obvious for them to have never seen in that space of time.
Continuity mistake: When Leanne first arrives, she kisses Luanne, and gets red lipstick marks on her. Later, when Leanne and Luanne are near the bathroom and Leanne says "I knew you would understand" (about Bill), she kisses Luanne, but there are no marks from her lipstick. Even if she mostly kissed Luanne's neck, at least part of some of the marks should show when Luanne turns to leave (after talking to Peggy).
Deliberate mistake: Why wouldn't Hank just use a credit card to cover the outstanding payment he owes on his insurace? It was established in the episode Rich Hank, Poor Hank that Hank has an emergency credit card and could easily use that and would be covered immediately. His panic over not having insurance would outweigh any problems he might have with using his credit card and the fact that he is dealing with an insurance company there is no conceivable way they wouldn't accept a credit card or ask if he has a credit card to cover the payment. The mistake seems to be deliberate as it sets the story up for Hank going somewhat over the edge with protecting the house.
Continuity mistake: As Hank is having his discussion with Cotton in the Casino you can see Cotton's red (playing) chips in front of him. In one shot Hank stands up and the angle shows Cotton from over Hank's shoulder and the red chips look black and badly damaged. The next shot from the same angle the chips are back to being red and completely fine. (00:19:55)
Continuity mistake: When Hank takes Connie to the doctors, he is in the waiting room. After Connie and the doctor come out they open the two doors and stand in front of the doors. Towards the end of the scene as the doctor is about to leave them, they have all moved far a short distance from the left of the doors.
Continuity mistake: In the scene when Lane Pratley comes into the woman's changing room after the first game he is holding the player's cheques by his waist. When the shot changes to a closeup of him the cheques have instantly moved to Lane holding them next to his chest.
Continuity mistake: When Cotton is trying to use the circular saw on the car dealer, the extension plug it's connected to gets disconnected around half way onto the alley road. The next shot its moved to just past the driveway, and the following shot it's now moved to about halfway down the driveway.
Continuity mistake: Bobby takes a bite of his brownie and leaves most of it on his tray when he starts to get up and the teacher comes over to talk about his attitude. A few seconds later, when he and Joseph start slamming their trays on the table, the brownie is gone. (00:17:45)