Other mistake: When Newt gives Jacob a suitcase full of eggs, he bumps into him, apparently swapping suitcases. If you watch carefully, the suitcases don't actually switch.
Other mistake: A shot of Jacob and Queenie walking was used twice. Queenie is showed on the left side of the screen and Jacob on the right, and Jacob looks behind, then turns to look to his left, then turns more in front of himself. This happens while Queenie and Jacob are trying to find Newt's case, then find what cell Newt and Tina are in when they are trying not to be killed by Grindlewald in disguise.
Chosen answer: It's not known why he gave up. Newt did have to leave New York and there was no point in continuing the search at that time.
raywest ★