It is mentioned on page 92 of the Runner's Companion that Spirits are specifically unable to "see or interpret simsense, electronic projections on screens, or AR displays".
The lack of being able to utilize simsense is perfectly understandable to anyone even mildly familiar with spirits, as it makes sense that as mana constructs they lack a biological brain with which to process the signals.
The other method of perceiving the matrix (through a physical display) presents more of a problem, at first glance. After all, what could possibly be preventing a spirit from seeing an object depicted on a screen when they can see the person standing right next to them when it uses the exact same sense (light detection)? Apparently, for spirits, it doesn't.
I suspect that spirits are actually blind to electromagnetic waves, and see things entirely through their astral senses. Thus, it makes sense that a spirit can see a person standing next to themselves, but be unable to detect output of a computer monitor.
