At the construction site, when Rachel finds the Andalite disc in cat morph, it is sticking out of the ground. When Jake goes to get it as Homer, it is completely under the dirt and Jake has to dig it up.
The hawk that Tobias admires at the Wildlife Rehabilitation Clinic and later acquires is not a red-tailed hawk. It is actually a Harris's hawk.
Chapman is frustrated at the Controllers for not noticing a Hork-Bajir footprint, but he doesn't notice the Andalite disc or Rachel as a cat when both are right at his feet. Rachel even audibly meows right before she runs back to the other Animorphs.