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I would agree that most of his verbal scores are consistent with each other, with the exception of Comprehension. If the examiner believes that that was not representative of his true ability, but more reflective of his attention and effort, then that is probably what it means, as that individual was able to directly observe test behavior. And if fatigue was a factor, it is worth noting that it is also the last subtest administered in nearly the entire cognitive battery (depending on which supplemental subtests were administered) (though Information is also a late subtest, and he did extremely well on that).
If by chance this is a real result (which, as noted, is an open question), some of the possible explanations for a relatively low Comprehension score include lack of real-life experience (sometimes affects very young test-takers whose verbal knowledge comes mainly from the particular genre of books they like), differences in cultural experience, challenges with receptive or expressive language (which is possible, even with very high verbal cognition), and personal weaknesses in social reasoning, despite the presence of intact or strong verbal cognition. (Not an exhaustive list.) BTW, the last item in particular can be accompanied by anxiety, which can be amplified by the gap between overall facility with language, and personal weaknesses with social language.
