Other mistake: Several scenes have palms in them or in the background. Story takes place in NH, so impossible for those trees to be there. Also, in the scene at their NH home out on the dock, their boat is registered in Georgia with the GA before the numbers clear as day.
Other mistake: The white horse looked very uncomfortable from what appeared to be an improperly placed bit (too far back and/or misaligned in its mouth). The handler should have noticed something was wrong and intervened. (00:20:30)
Other mistake: Laura's Arizona license plate (G 652P) was, understandably, a combination or blending of the design from Jan 2008 - Apr 2020 (blue/white/yellow horizontal colors) with a serial format closer to that of the mid-1950s, but improper for either time period. The 2008 - 2020 plate serial format was "ABC 1234." Laura's 1955 plate - when the serial format was "A - 12345" - should not have had a letter ("P") on the far right. ("G" could be the code for Gila, Graham, or Greenlee County, but which one?). (01:24:19)
Other mistake: When Marilyn is standing on the subway grate and the skirt is billowing up, there is one of the takes where there is a dark spot near the front of the skirt. All others are spotless.
Other mistake: Jamie was strangling Rose with both hands, quite forcefully, for almost a minute until his dad hit him over his head. When Rose was getting up, her neck was not the least bit red and did not show any signs of having been choked. (01:05:05 - 01:06:03)
Other mistake: The GPS voice said, "Your destination is on your left", but Kath kept driving (slowly) on the dirt road and did not reach the cabin for over 30 seconds (longer than would be expected). A GPS system typically announces how many feet until you reach your destination, plus "You have reached your destination" after traveling that number of feet. (00:05:00 - 00:05:38)
Other mistake: In the last scene at the airport, extras get reused - for instance, when she says "I promise..." a guy with a loud teal T-shirt, dragging a little trolley, walks by her. The commissioner offers to give her a ride, and the same guy is walking in the opposite direction. (01:20:50)
Other mistake: Richie, with a bullet hole through his right side, arrived at Leonard's and thrashed about on the table while his wound was being stitched. He was even turned over so that Leonard could stitch the back side (exit wound). Richie's hair became somewhat disheveled during the procedure, but after he recovered and walked into the other room, his hair was neatly combed/styled and his suit/tie showed no wrinkling or signs of blood on them (unlike his shirt around the wound). (00:22:00 - 00:33:55)
Other mistake: Si was kneeling on the floor, stabbing his upper left arm and blood was gushing out. After he moved his right arm with the bloody knife to his right side, the aerial view did not show any blood on the floor, across his thighs/pants, or even dripping down his left arm. (00:27:50)
Other mistake: It is unrealistic that Solomon could drag the long rope through a wooded area for years without the rope getting frayed/worn out and that the rope did not get snagged or caught in shrubs, around tree trunks, etc.
Other mistake: In the origin story of Poirot's facial hair, we see the damage on his cheek is massive, well into the cheekbone. His girlfriend says he'll grow a moustache to cover it, and surprisingly, it works - nevermind the fact that scar tissue wouldn't grow hair. When we see the scar without the moustache, while smaller than the initial damage, it still extends into the cheek at the level of the nostrils in a way that the 'stache couldn't seamlessly cover like in the rest of the movie and its prequel.
Other mistake: The plea deal with Danny (5 to 7 years in prison) seems inconsistent with Georgia's sentencing guidelines, recidivist law, and the State's reputation as being tough on repeat offenders. Danny was on parole, which means he was convicted of a felony. His new charges - including assaulting a police officer (an "aggravating circumstance") and possession with intent to deliver - could be enough to impose MAXIMUM sentences or mandatory minimums (10 years?) under sentencing enhancements.
Other mistake: At the end the camera bulbs would not work as they are electric. This is proven when the music starts after the creature leaves the area. (02:01:00)