When the little girl is opening the door to go out for the first time you can see she has one bare foot but when she actually goes outside she's suddenly wearing two different coloured socks.
Agent Ray says to Henry, "I can still smell the hydrogen peroxide on your face." Hydrogen peroxide is an odourless compound, which breaks down into oxygen and water: both odourless. Agent Ray would not be able to smell any trace of the peroxide.
Grandpa is driving the Ice Cream truck and hears a police dispatch, and reaches over to turn it off, however it's actually a CB radio, which is incapable of picking up any frequencies that would be used by a police department.