In the FAQ-thread Aaron suggested to put this into the Errata thread:
The Spirit Basics entry on p. 301 states (emphasis mine):
When materialized, the spirit uses astral perception (its only perception) to perceive the physical world.
The sentence just before this quote suggests, that materialized spirits can see physically (colors, transparent glass etc.) and astrally (emphasis mine):
The spirit is dual-natured while it’s materialized, which means it exists simultaneously on the physical and astral plane, meaning it can see objects in both places
Additionally:
All spirits have Perception, which would be useless, if the quoted sentence is correct, because they could always use Assensing.
Normally (and in SR4) one could argue, that a materialized spirit is dual-natured and the "Dual-natured" critter power stated that " that a dual-natured critter always senses both the physical and astral worlds". But with this "astral perception (its only perception)"-quote specific would trump general and materialized spirits wouldn't be able to see colors, see through glass, hear words exactly (not muffled like from astral space), see photographs etc.
Is that intended?