When Malorie and Olympia are about to give a birth Gary puts vinyl record on, to play Haydn's Piano Sonata (HOB. XVI: 32). However, the record label is Capitol, which not only never recorded or released this sonata, but is also the last label to use/show with piano music in general, the only pianist they ever had under contract was Leonard Pennario and that's all. Pennario did record one Haydn's sonata (of ~62 in total), but not this one.
When the trio is reunited after Molly tumbles down a ravine, they are in a group hug, and Girl's blindfold is very loosely tied in the back-- almost ready to fall off. But when they the start to walk again, her blindfold is securely fastened.
When Gary arrives in the kitchen, his blindfold is on the floor to his right just out of reach. It's in front of him in the next shot, then he picks it up off the floor from his right, without having to reach for it.
The Jeep Grand Cherokee proximity sensors do not cover all sides of the vehicle, just front and rear. Also the only colors used on Grand Cherokees for proximity sensor screen is yellow and red, green is not used.
When two injured characters are fighting over a pump-action shotgun, the scene cuts to Malorie listening to them from another room. Two gunshots follow, and the second is too soon after the first for the gun to have been pumped.
The people have a supply of electricity although most of humanity no longer exists. Depending on how it's generated, not much human intervention may be needed to generate power. The Hoover Dam can operate for up to 2 years without human intervention.
At the beginning of the movie, Malorie and her sister had been seeing reports on the news about mass suicides and chaos in other countries. Then later, Greg kills himself after seeing the entities on the home surveillance monitors, suggesting that a person can become afflicted even by seeing an image of the entities on video. If the entities could also be seen on video, anyone who'd been watching news coverage of the chaos would have been afflicted as well.
But only if that coverage actually showed the entities ; in which case the camera crew on site would have died, and their video would not have been sent on. The only broadcast video, was therefore that which did not actually show the entities.
Cell phones, televisions, and communication systems stop working the first day Malorie enters the home, but the car's GPS works days later. Cell phones have a range of about 40 miles, and require towers. Televisions require either a physical landline or a local broadcast tower, either of which could lose power or be turned off. GPS uses satellites 12,000 miles above the earth, sending radio waves that cover the planet. Standalone GPS devices existed before the invention of smartphones. The satellites would need continuous control (currently from Schriever Air Force Base in Colorado, or Vandenberg Air Force Base in California) but it would likely be maintained as a priority by any working remnant of the US Air Force.
When they arrive back from the mall (51:56) and see the house from outside, there are newspapers plastered on the outside of windows on the 2nd floor, while the windows next to it have newspapers on the inside of the glass.