People are reading too many spy novels...
People who work with classified information know things. Classified things. Classified things that are as easy to remember as people's names, IP addresses, or someone's birthday. They don't need eidetic memory to know them, they just remember them. TS/SCI is not only broadly classified by level and need to know, it is specifically restricted (compartmentalized), so the relationship of fairly trivial to remember information to something that else makes it classified. It sounds to me that Person A sent an e-mail to person B with said e-mail contents containing some amount of information (possibly very small) that Person B wasn't authorized to know. It could have been people's names, it could have been IP addresses, it could be some dates/times.
Perhaps the individual in question can use the HRC defense.
Biting the hand that feeds IT
