It would be nice if we could set the position or give an offset to the AI Stimuli source, as for a usual Character blueprint it’s tied to their origin which is usually the pelvis. In that, if the pelvis is behind a waist high wall or something they are invisible to AI perception, but they shouldn’t be since the rest of the body is visible. It would be nice if we could set the offset or give a position entirely manually, so that way we could set it to be the head or something so they would be visible to the AI perception even if the groin isn’t.
If you know a little bit of C++, add IAISightTargetInterface to the character and then override the CanBeSeenFrom function.