Near the beginning when Toshio is sending a fax he places the pages in the machine face up, yet as the page moves through the machine we can see the logo which clearly shows this machine expects pages to be placed face down. The fax is later shown being read by Simon and has been correctly received.
When Wayne is holding Simon at gunpoint and you can see the computer screen showing the progress of the stock market in the background, the line chart changes from being half way across the screen to beginning to cross the screen to being half way across the screen again by the time the scene ends.
In the first scene at the school house, the date, Monday 20th March 1977, is written on the chalkboard. March 20, 1977 was a Sunday.