Like my child...
Teacher knows better than me, of course, so when I explain due to past experiences (prior to adoption) LO will freeze if she's afraid, and is in general very anxious. She hides it because it makes her feel vulnerable. I explain the sorts of things that will make her afraid (adults being angry). Teacher seems to think I'm one of those neurotic parents because she can't see any difference between LO and the others.
Teacher (to use the words of the psych who ended up observing LO in class) maintains discipline by making the children afraid of her.
LO shuts down. Teacher decides this is 'defiance'. Piles on the detentions. LO shuts down further... Teacher suggests I need parenting classes... LO not cognitively able enough for mainstream (despite pre-school having no difficulties, including with her behaviour)...
Sadly this scenario is all too common among friends who are adoptive parents as well.
Luckily once psych came in (and involved SENCO who refused to meet with me until psych got involved) they were finally willing to listen to what I said. LO is now coping, and cognitive assessments show that she is well within mainstream ability, and above average in some aspects.
Sometimes children who seem FINE are falling apart inside, and their parents are the ones who can see that (and have to deal with the fall out).