While it might be as simple as a social phobia or anxiety, I'm inclined to think/hope that the text at the end of chapter 6 referring to "what will be reflected in those eyes" is a clue, and that she's overwhelmed by crowds due to having a skill like Observe, but with no way of shutting it off. So it's just a constant deluge of info boxes or something.
It probably isn't that, but it'd be a bit more interesting if it's another (snrk) Skill Issue than it being something relatively mundane.
Needing a special disconnected/outbuilding, seemingly airlocked bedroom to prevent yourself from accidentally turning your family into corpsicles in your sleep is traumatic (and interesting) as fuck. Having this girl's problem be something relatively minor would feel imbalanced. Her having agoraphobia or being afraid of crowds as a side effect to a Skill Issue (much like Kamui's closed off emotions are a symptom/stopgap measure of her icy blessing) would be fine though.