Nyx seems to be a Bugblatter Beast in reverse - if she can't see you, you can't see her. This has become a noticeable habit recently; if visitors drop by unexpectedly, or come into a room where they weren't before, she squeezes her eyes shut and turns her head away from them. This can go on for five minutes or as much as fifteen. She doesn't fuss, just "goes invisible."
It's what's called Avoidance Behaviour and while everyone does it in some situations, for ASD folk it can become problematic. I'm adding it to the list of things to discuss with our therapy team in September.
Meanwhile, we are trying to respect her need/feelings and not push her to interact with people until she is ready to. It's a little frustrating for everyone, but our friends and family are very loving and supportive and patient.