Around the 1:10:00 mark, just before Harper says "This is the best meal that I've ever had in my entire life", she rips a smaller piece from what little is left of the slice, folds it, and as it goes into her mouth the scene abruptly cuts to her holding a larger, unfolded piece.
At the 20 minute mark, when Harper and Charlie are at the office late drinking scotch together, the position of her legs change from both being on the desk, to one leg on the floor, and back again.
When Rick exits the club (at about the 4:00 minute mark), he has Charlie twist the cap off of his green juice drink. Charlie never hands the cap to Rick, yet you see him fully twist the cap on as he approaches the arriving car. In the next shot, the cap is back off, and Rick's left hand is down by his side (he is holding the bottle in his right hand). In the following shot, Rick's left hand is on top of the bottle twisting the cap on again.
In the last scene when Harper and Charlie meet outside, it seems that extras were not used for the crowds outside. As a result, you see that each person in passing is taking a good look at what is going on in curiosity, and one man in orange is captured watching the camera move upwards towards the skyline.
In the pool party scene, the same extra (blonde female in blue bikini) can be seen behind Harper (dancing) and Charlie (at the bar) as the camera switches from one of them to the other.
When Charlie goes to call Harper, his phone contacts are only engineered up to the end of H. After that, he has two under J (Jorf and J Bo), and the next visible letter is R. Additionally, his phone says No SIM, which leads us to wonder how he plans to call anybody really.
Actual footage from a Yankees-Red Sox game is used in the scene where the main characters try to get Kirsten and Rick on the kiss cam. However, the announcer's comments are fake - for example, at one point he says Andrew Benintendi is batting for the Red Sox, but the player shown is definitely not Benintendi (it appears to be Rafael Devers instead)