How many instances are there of doctors and specialists missing an illness in a patient?
People, even those who are the best in their fields aren't mind readers or soothsayers. Unfortunately, one can have all of the knowledge, experience and education but still mistakes can and do happen
Do we even know what the actual extent of creep face and KR's educational relationship was? Like I remember reading bits but cannot recall properly. Were the lectures in person or over zoom? Were they all 121 or group settings? I gather she will have looked over work of his maybe, but to what extent? I'm asking as I'm thinking if Katherine was his professor and he was one in a class of a dozen that she gave lectures to a couple years prior to the night of the crime, would she have remembered his name IF he hasn't have done this and ended up in the media y'know? Maybe enough to say oh yah I remember he was in my class, I dunno. She was one of a bunch of lecturers on that course so wasn't his primary professor (like his tutor) right?
If it's what I think is likely and he was just one in a class of many classes she taught and she spent a very small amount of time conversing 121 with him, if at all, then even with a 6th sense - how could she see what he was hiding deep under his people suit?
I dunno, I'm half asleeps and babbling