Continuity mistake: When Zack first approaches Normal a package materializes on the left side of Normal's desk. (00:07:40)
Continuity mistake: At the end of the impromptu job interview, there is a flat package partially covering a magazine on the right side of Normal's desk. It's gone as Zack walks away. (00:08:10)
Continuity mistake: When Max shows Logan the classified ad, he is holding the newspaper only with his right hand. Cut to Max and the other side of the paper is also raised. (00:08:15)
Answer: Max's disease is specifically tailored to work only on cells exhibiting Logan's genome. No one else would notice it.
Phoenix