I'm inclined to go with geofizz's line of questioning. Couldn't this be a language pragmatics issue? Poor ability to answer questions can be a red flag for that, can't it? (How/because rang a bell for me there.) How is her writing?
My DD has a tendency to overthink stupid reading comp questions, but I always *understand* why she overthought them when she explains why. It's not random and mysterious. It's typical giftie stuff, made a bit worse by her tendency to be overliteral and overprecise at times. She writes great short answers, but multiple choice questions where they're all kind of poor answers will frustrate her into a corner sometimes.
