Doesn’t mean it doesn’t deeply affect you. My GenX exes, while I am still on very good terms with them, were extremely dismissive avoidant. You got too close or got them too vulnerable, they almost immediately shut down and/or freak out. Then they went back to believing everything was a-okay.

That may not be a childhood trauma. It sounds like someone recoiling from someone taking advantage of their vulnerability. Probably unconsciously, and once the trigger went away the response does too. Still sounds like therapy could at least make them aware of it.