Sick<br>I went to work yesterday. I began to cough. I went into the bathroom to clean up. I saw that I was very sick. I went home early from work.
They missed work because of their illness
The person went home early from work, so they missed at least part of a day. The system presumably could not understand the difference between leaving work early and missing work. 
( z1 miss :ARG0 ( z2 they ) :ARG1 ( z3 work ) :ARG1-of ( z4 cause :ARG0 ( z5 ill :ARG1 z2 ) ) )