Audio problem: When the boy and the leader of Iceland are hammering in posts and the boy is complaining that he's the heir and shouldn't have to do manual labor, there are at least two times when bad wind flutter in the microphones can be heard. It sounds like the wind clips the volume level and the audio briefly cuts out. It happens on windy film shoots, as wind screens can only prevent so much and its obviously very windy in this scene. Why this wasn't caught in post is hard to say. This is audible on the video on demand version.
Suggested correction: No such problem exists on the UHD/Blu-ray release. I also did not notice it on the VOD release, so it could have just been an issue with your sound setup.
Continuity mistake: Although Adeline has her mouth to the ground (eating grass), her head is suddenly upright and still in a few views of Kay or Terry. The most noticeable sudden change in Adeline's head being upright occurs right after Adam hugs her. (00:34:34 - 00:35:00)
Revealing mistake: When William and Jack open the door, enter the room, and walk past the helium-filled balloons (tied to a chair about 4' away), the balloons remain immobile. Due to how light helium balloons are, just opening the door or breathing nearby would be enough to cause the balloons to move somewhat - if they were actually there. (00:16:00)
Character mistake: Nolan said, "Everybody knows that no sharks swim in freshwater" and Spencer said, "They don't come into freshwater", but there are freshwater sharks (e.g, river sharks) and bull sharks (not true freshwater sharks) can survive in saltwater or freshwater. Jacob Harper (National Aquarium) pointed out eyewitness accounts of sharks swimming up the Mississippi River and "bull sharks have kidneys that recycle salt" but did not mention the glands near their tails that help keep salt in their bodies. (00:08:08 - 00:29:50)
Factual error: Pettis' calculation of the amount Connor needed to replace his asset was way off. He stated, "[Cornell] brought me about 250 [$250,000] a year. He had at least 20 more years of service. Subtract five years he might have spent in prison, so you owe me, what? Six point two million." Pettis was presented as intelligent, but a quick mental calculation of even the full 20 years at $250,000 would total only $5 million (not $6.2 - an odd sum). For 15 years, the total would be $3,750,000. (00:28:45)
Continuity mistake: Alan goes into his appointment with Dr. Fredericks at 5:08, and it is still 5:08 on the wall clock when he leaves her office. (00:10:20 - 00:14:03)
Continuity mistake: The orange feather toy that was in the cat bed with the cat when Sam got to the bookstore was not there a couple camera shifts later. (00:25:33 - 00:26:25)
Continuity mistake: During their first encounter (the first we see in the movie, at least), Sheila sits next to Gary, and they both order Old Fashioned. Phil the Bartender makes a comment on that, and she shoos him off. Look at Kaley Cuoco 's bag; one of the straps keeps going on/off the top of the bag between shots. (00:03:30)