Ive noticed it before but thought I'd explain a specific incident. Last week friend hosted a birthday party for her ds. She said dd remained in the kitchen with her mum, mil and grandmother etc.. Stayed there for a long time because too shy to join the other children - who she all knows thru nursery. But...she really charmed all the adults. Chatted to them confidently and they thought her delightful.
Very curious as to why she is like this! Friend's mum is an experienced teacher and she had never seen it, so that got me really wondering.