The Raccoon - S1-E10
Character mistake: Charles takes a bowl of water to Jack. Jack steps away from the water, and doesn't drink. Then a couple of scenes later, when Caroline and Charles are in the barn, Mary comes out and says Laura is thirsty. Caroline starts crying and says that Dr. Baker says that it's a sign, but a sign of rabies is actually when the person or animal doesn't want water. At one point, it was called hydrophobia because of the fear of water. (00:38:26)
Christmas At Plum Creek - S1-E14
Character mistake: When Charles explains to Carrie about Christmas, he mentions 3 kings and 3 wise men. The bible refers to them as Magi or Wise Men and no clear evidence on whether there were just 3, or if they were even kings. Putting aside the number of visitors and what they were called, it's either kings or wise men, but not both.
Character mistake: When Eric is asked to spell repetitious at the spelling bee he spells it R E P I T I T I O U S... Alice Garvey says "correct" but it was incorrectly spelled.
Times Are Changing (1) - S9-E1
Character mistake: Almanzo says he hasn't seen his brother Royal in 10 years, but in fact he saw him not long ago as he looked after his 2 sons who were terrors, and at that time Royal didn't even have a daughter.
Suggested correction: Royal's wife was pregnant when he visited years before Laura had the baby.
What happened to Pearly Day? Almonzo's younger brother?
Not sure if this varied in the show, but in real life Pearly Day had six children and died in 1934 just a month prior to his 65th birthday.
Almanzo had 2 brothers. Royal and Jenny's dad, the one that was dying.
That may not work, unless Laura and Almonzo were not married yet at the time of Royal's first visit, but it is a good suggestion.
In the TV series, the episode that they were taking care of the boys was only six episodes before Laura found out she was pregnant, and Nellie's babies were still babies throughout that time so it wasn't that long. And Rose wasn't that big When they came to visit, so it was probably only 1 1/2-2 years of a time gap. Also, when Royal and Jenny came to visit, Almanzo introduced Royal to Laura as if they had never met before.
It was NOT years! Royal, his wife and 2 sons visited Almanzo in Season 7. His wife did announce she was pregnant in the end. However, when Royal comes back to visit with Jenny, at the beginning of Season 9. If Jenny is supposed to be the baby Royal's wife was pregnant with then she would have still been a year old or 2 at most. They do explain that his wife died, but what about those boys? They would have been early teens by then. Nothing is ever said about them or why they aren't with Royal.
But Laura says "glad to finally meet you Royal", when he came with Jenny. But she met him when he came with the boys.
Home Again - S9-E16
Character mistake: Mrs. Oleson, talking to Willie, tells "Albert" to go clean up his room while Mr. and Mrs. Oleson, Willie, and Albert are talking in the Mercantile. (00:39:20)
Suggested correction: Mrs. Oleson isn't calling her son 'Albert'. She is talking to Albert as he's leaving the store and says "Well, it's nice to have you back, Albert" then she turns and looks at Willie and tells him to clean up his room. There is a slight pause between "it's nice to have you back" and "Albert" but she is not looking at Willie when she says Albert's name.