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.
Gone with the Windstorm - S9-E13
Continuity mistake: Just after Dale, Nancy and Peggy get past the police blockade in the news van there is an overhead shot of the van and you can see Dale doesn't have his fake moustache on anymore. The next shot he is taking off the fake moustache.
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.
Gone with the Windstorm - S9-E13
Continuity mistake: As Hank jumps out of the closest to scare the boy that is scaring Bobby, we see the contents of the cupboard as well. We see a shelf with a large number of boxes. Clothes rail with many clothes hanging on it. Finally an assortment of objects on the ground. When Hank leaves and the father is wondering where his son has disappeared to we see inside the cupboard again. Everything including the shelf, clothes and clothes rail have disappeared. The only thing remaining is one small box in the left corner.
Redcorn Gambles with His Future - S9-E11
Other mistake: In the season four episode "Nancy Boys", when Nancy calls John Redcorn and tells him that she wants him back, he says, "I'm thirty-six years old. I don't need this crap." But here while John is talking to Hank, he mentions waking up one day and realizing that he is forty. If four years had passed since his break-up with Nancy, then Bobby and Joseph would now be sixteen and at least sophomores in high school, but they are still in middle school.
Death Buys a Timeshare - S9-E3
Plot hole: During a heatwave, the Hills are dying from the heat and even look for a pool to swim in to cool off.This makes no sense, they live in a ranch house which would have central air or at worst some window air conditioners.
A Rover Runs Through It - S9-E1
Continuity mistake: At the beginning of the episode, after Peggy's mother calls, Hank says "What's it been? Twenty years?" But they spoke with Peggy's mother during the events of the episode "Happy Hanks Giving." Hank spoke to her on the phone, Peggy shouted at the phone, and Hank commented on Mrs. Platter not approving of propane.
Other mistake: In this episode, Peggy is terrible at gardening. In the fourth season, she brought flowers to the man who was making foot fetish videos. She said that the flowers were "so pretty" and were from her "own garden."
Answer: Jeffrey Boomhauer is a Texas Ranger as can be seen in the final episode at the end when he sets his wallet down, it flips open revealing a Texas Ranger badge.