When Bick and Leslie first arrive in Texas by train, they disembark into a major dust storm. In the next shot, of Leslie walking toward her horse, the air is suddenly completely clear.
Near the end, when Jett and Luz are in the bar together, the amount of liquor and ice in Jett's glass changes.
When Luz II puts in her request for a private phone, the position of her right arm changes between long and close shots.
When Jett is talking to the oil executives about "cracking Benedict", he is seen from behind with a cigarette in his mouth, but then is seen shortly after from the front with the cigarette in his hand.
When Uncle Bawley makes his "99% beef" joke, he is shown in the long shot holding his drink in one hand, but in the subsequent close shot, he's holding it in both hands.
In the Jett Rink Airport opening day parade, there are riders on horseback carrying an American flag and a Texas flag. The American flag being carried has 37 stars (should have been 48), and the lone star on the Texas flag is upside down. (The stripes are right side up.)
One of the oil men says the oil tax exemption is the best thing to happen to Texas since the defeat of Geronimo. Geronimo was a Chiricahua Apache and surrendered in Arizona.
The name Luz is pronounced in the way that English speakers say the word "loose". The Texans would have learned Spanish as children from the ranch help, and that's how they would have said it. (The pronunciation was likely changed so that audiences wouldn't laugh.)
The large display of flags in the lobby of the home has the American flag in the wrong position. It is on the right, as we see it. However, protocol requires Old Glory is to be presented "on the flag's own right," (aka stage right) meaning our left. While this may normally be correct, the display of flags are the "Six Flags over Texas". A quick Google image search will verify that these flags are consistently displayed in the following (generally chronological order) from left to right: Spain, France, Mexico, Confederate States of America, Republic of Texas and the United States of America. As such, the display as depicted in the film is accurate.
During the confrontation between Bick and Jett in the hotel banquet hall stockroom, Bick throws a "basket" knocking over several storage shelves. The shelves start to fall before the basket makes contact.
Near the end, Bick knocks over a shelf of wine bottles, causing a cascade of shelves knocking the next one over. The scene cuts to Jett and you can hear a large number of shelves falling over. However, when the scene cuts back to Bick exiting, there are only three shelves (with the third leaning against the wall), and the other "shelves" behind are just a set painting.
In the scene where Leslie faints at the barbecue, long shots show Luz standing at a table with no one behind her. But in the close-up after Leslie faints, when Luz says, "That's what I was afraid of", there is a crowd of people in the background behind her.
When Jordan forces his son to ride his horse with him at a gallop, the child dummy is clearly slipping down out of the rider's grip as he comes to a stop. The immediate close-up has the child actor sitting perfectly erect.
When Jordy introduces his new wife Juana at the pool party, the people behind Bick and Leslie are seen applauding, even though Jordan hasn't finished his announcement yet. Also, no sound of clapping is heard.
When little Jordan is crying because he is afraid to ride the pony, there is a large Texas flag hanging in front of the mansion. The star on the flag is upside down.
The newspaper announcing Angel Obregon's homecoming has an article headlined "Full-Paid Taxes Record Broken". The text of the article refers to Los Angeles county and Howard L. Byram. Byram was the Tax Collector for Los Angeles county in California. It's unlikely a story like this about LA would be in a Texas newspaper. It appears that the production used a real California newspaper and added the picture of Angel.
At about 1:17:15, when Leslie has dropped the first hint to Bick that she's pregnant, the creak of the camera dolly can just barely be heard as it pushes in for a closer shot.
The newspaper shown announcing Angel Obregon's return has an article about Alfred Chester Beatty giving up his American "nationality" and becoming a British citizen. Beatty was a real person who did this in 1933. The newspaper shown is from that year when it should have been from sometime between 1941 and 1945.
When the story moves to WWII era, the fashions and hairstyles of the female character are strictly that of the 1950s, not early 1940s.
During the welcome barbecue for Leslie after her and Bick get married, there is a long shot of the ranch and in the sky there is a jet contrail in the distance. Since the opening scenes take place in the 1920s, there were no jets at the time.
At the pool party, the square dancers' moves do not match the caller's instructions.
When Leslie and her children return to Maryland for Thanksgiving, they are greeted by a green midsummer landscape. At that time of year, the leaves and grass would have already turned and the trees would be well on their way to being bare.
The opening sequence shows Bick arriving in Ardmore, MD on a Chesapeake and Ohio (C&O) passenger train. Ardmore did not have train service and the closest line was the Pennsylvania Railroad. The C&O did not have service in Maryland. It did have service in Charlottesville, VA where the Maryland scenes were actually filmed.
Shortly after Leslie prepares breakfast for the first time in the ranch, surprising Luz, and as Bick walks down the stairs, a microphone is briefly visible above the shot.
After Bick takes his crying toddler son for a short ride and Leslie is helping their son off the horse, the camera moves upward revealing a boom microphone at the top of the screen. Seconds later, when Bick dismounts the horse, the mic is seen once again.
A group of Texas landowners talk about Geronimo as chief of the Comanche. He was an Apache and not a chief, but a shaman.
At the end of the parade, just about to enter the Benedict limo, Leslie answers Bick's question about whether she knew that Luz would be Queen of the Parade, and she answers: "I didn't know, Jett," instead of "Bick" or "Jordan." The car obscures Elizabeth Taylor's face, but the sound and closed caption both came out "Jett".
At the dinner table in Maryland, Jordan Benedict states that his ranch is 595,000 acres. Later on Leslie refers to Reata as being 500,000 square miles. An acre equals 1/640th of a square mile. The state of Texas is only 267,339 square miles, so Leslie was saying that the ranch was almost twice as big as the entire state.
The U.S. flag on the casket at the train platform is displayed incorrectly, with the field of stars on the right, but then correctly at the burial, with the field of stars on the left.
The flags in the Benedict house are displayed backwards. The U.S. flag should be on its own right (the observer's left) when displayed with other flags.